Enclosing a pen with a postal questionnaire can significantly increase the response rate

Strategies to increase survey participation: A randomized controlled study in a population of breast cancer survivors

BACKGROUND

Data collection by mailing questionnaires to the study population is one of the main research methods in epidemiologic studies. As participation rates are decreasing, easy-to-implement and cost-effective strategies to increase survey participation are needed. In this study, we tested the effect of a pragmatic combination of evidence-based interventions.

METHODS

We conducted a two-armed randomized controlled trial, nested in a cohort of breast cancer survivors (n = 1000) in the setting of a health outcomes survey. The intervention arm received a postal pre-notification, a non-monetary incentive (ballpoint with the study logo) and an alternative invitation letter in which several lay-out and textual adjustments were implemented according to behavioural science techniques. The alternative invitation letter also contained a QR-code through which an information video about the study could be accessed. The control arm was invited according to standard practice. Participants had the option to fill-out a questionnaire either on paper or online. A questionnaire with more than 50% of the questions answered classified as participation.

RESULTS

Overall participation rate was 62.9%. No significant difference in participation rate was observed between intervention and control arm (64.5% vs 61.3%, Risk Ratio (RR) 1.05, 95% CI [0.96 - 1.16]). Older age at study (>65 vs <51 years), and high socio-economic status (highest vs lowest quartile) were associated with higher participation rates (RR 1.30, 95% CI [1.07 - 1.57] and 1.24, 95% CI [1.09 - 1.42] respectively). In-situ carcinoma compared to invasive cancer and longer interval since treatment were associated with lower participation (RR 0.86, 95% CI [0.74 - 0.99] and RR 0.92, 95% CI [0.87 - 0.99] per 5 year increase, respectively).

CONCLUSION

Overall, the combination of four interventions tested in this study did not improve survey participation among breast cancer survivors. The overall participation rate was relatively high, possibly due to the study population of cancer survivors.

Undertaking Studies Within A Trial to evaluate recruitment and retention strategies for randomised controlled trials: lessons learnt from the PROMETHEUS research programme

Background

Randomised controlled trials ('trials') are susceptible to poor participant recruitment and retention. Studies Within A Trial are the strongest methods for testing the effectiveness of strategies to improve recruitment and retention. However, relatively few of these have been conducted.

Objectives

PROMoting THE Use of Studies Within A Trial aimed to facilitate at least 25 Studies Within A Trial evaluating recruitment or retention strategies. We share our experience of delivering the PROMoting THE Use of Studies Within A Trial programme, and the lessons learnt for undertaking randomised Studies Within A Trial.

Design

A network of 10 Clinical Trials Units and 1 primary care research centre committed to conducting randomised controlled Studies Within A Trial of recruitment and/or retention strategies was established. Promising recruitment and retention strategies were identified from various sources including Cochrane systematic reviews, the Study Within A Trial Repository, and existing prioritisation exercises, which were reviewed by patient and public members to create an initial priority list of seven recruitment and eight retention interventions. Host trial teams could apply for funding and receive support from the PROMoting THE Use of Studies Within A Trial team to undertake Studies Within A Trial. We also tested the feasibility of undertaking co-ordinated Studies Within A Trial, across multiple host trials simultaneously.

Setting

Clinical trials unit-based trials recruiting or following up participants in any setting in the United Kingdom were eligible.

Participants

Clinical trials unit-based teams undertaking trials in any clinical context in the United Kingdom.

Interventions

Funding of up to £5000 and support from the PROMoting THE Use of Studies Within A Trial team to design, implement and report Studies Within A Trial.

Main outcome measures

Number of host trials funded.

Results

Forty-two Studies Within A Trial were funded (31 host trials), across 12 Clinical Trials Units. The mean cost of a Study Within A Trial was £3535. Twelve Studies Within A Trial tested the same strategy across multiple host trials using a co-ordinated Study Within A Trial design, and four used a factorial design. Two recruitment and five retention strategies were evaluated in more than one host trial. PROMoting THE Use of Studies Within A Trial will add 18% more Studies Within A Trial to the Cochrane systematic review of recruitment strategies, and 79% more Studies Within A Trial to the Cochrane review of retention strategies. For retention, we found that pre-notifying participants by card, letter or e-mail before sending questionnaires was effective, as was the use of pens, and sending personalised text messages to improve questionnaire response. We highlight key lessons learnt to guide others planning Studies Within A Trial, including involving patient and public involvement partners; prioritising and selecting strategies to evaluate and elements to consider when designing a Study Within A Trial; obtaining governance approvals; implementing Studies Within A Trial, including individual and co-ordinated Studies Within A Trials; and reporting Study Within A Trials.

Limitations

The COVID-19 pandemic negatively impacted five Studies Within A Trial, being either delayed (n = 2) or prematurely terminated (n = 3).

Conclusions

PROMoting THE Use of Studies Within A Trial significantly increased the evidence base for recruitment and retention strategies. When provided with both funding and practical support, host trial teams successfully implemented Studies Within A Trial.

Future work

Future research should identify and target gaps in the evidence base, including widening Study Within A Trial uptake, undertaking more complex Studies Within A Trial and translating Study Within A Trial evidence into practice.

Study registration

All Studies Within A Trial in the PROMoting THE Use of Studies Within A Trial programme had to be registered with the Northern Ireland Network for Trials Methodology Research Study Within A Trial Repository.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 13/55/80) and is published in full in Health Technology Assessment; Vol. 28, No. 2. See the NIHR Funding and Awards website for further award information.

Methods to increase response to postal and electronic questionnaires

BACKGROUND

Self-administered questionnaires are widely used to collect data in epidemiological research, but non-response reduces the effective sample size and can introduce bias. Finding ways to increase response to postal and electronic questionnaires would improve the quality of epidemiological research.

OBJECTIVES

To identify effective strategies to increase response to postal and electronic questionnaires.

SEARCH METHODS

We searched 14 electronic databases up to December 2021 and manually searched the reference lists of relevant trials and reviews. We contacted the authors of all trials or reviews to ask about unpublished trials; where necessary, we also contacted authors to confirm the methods of allocation used and to clarify results presented.

SELECTION CRITERIA

Randomised trials of methods to increase response to postal or electronic questionnaires. We assessed the eligibility of each trial using pre-defined criteria.

DATA COLLECTION AND ANALYSIS

We extracted data on the trial participants, the intervention, the number randomised to intervention and comparison groups and allocation concealment. For each strategy, we estimated pooled odds ratios (OR) and 95% confidence intervals (CI) in a random-effects model. We assessed evidence for selection bias using Egger's weighted regression method and Begg's rank correlation test and funnel plot. We assessed heterogeneity amongst trial odds ratios using a Chi2 test and quantified the degree of inconsistency between trial results using the I2 statistic.

MAIN RESULTS

Postal We found 670 eligible trials that evaluated over 100 different strategies of increasing response to postal questionnaires. We found substantial heterogeneity amongst trial results in half of the strategies. The odds of response almost doubled when: using monetary incentives (odds ratio (OR) 1.86; 95% confidence interval (CI) 1.73 to 1.99; heterogeneity I2 = 85%); using a telephone reminder (OR 1.96; 95% CI 1.03 to 3.74); and when clinical outcome questions were placed last (OR 2.05; 95% CI 1.00 to 4.24). The odds of response increased by about half when: using a shorter questionnaire (OR 1.58; 95% CI 1.40 to 1.78); contacting participants before sending questionnaires (OR 1.36; 95% CI 1.23 to 1.51; I2 = 87%); incentives were given with questionnaires (i.e. unconditional) rather than when given only after participants had returned their questionnaire (i.e. conditional on response) (OR 1.53; 95% CI 1.35 to 1.74); using personalised SMS reminders (OR 1.53; 95% CI 0.97 to 2.42); using a special (recorded) delivery service (OR 1.68; 95% CI 1.36 to 2.08; I2 = 87%); using electronic reminders (OR 1.60; 95% CI 1.10 to 2.33); using intensive follow-up (OR 1.69; 95% CI 0.93 to 3.06); using a more interesting/salient questionnaire (OR 1.73; 95% CI 1.12 to 2.66); and when mentioning an obligation to respond (OR 1.61; 95% CI 1.16 to 2.22). The odds of response also increased with: non-monetary incentives (OR 1.16; 95% CI 1.11 to 1.21; I2 = 80%); a larger monetary incentive (OR 1.24; 95% CI 1.15 to 1.33); a larger non-monetary incentive (OR 1.15; 95% CI 1.00 to 1.33); when a pen was included (OR 1.44; 95% CI 1.38 to 1.50); using personalised materials (OR 1.15; 95% CI 1.09 to 1.21; I2 = 57%); using a single-sided rather than a double-sided questionnaire (OR 1.13; 95% CI 1.02 to 1.25); using stamped return envelopes rather than franked return envelopes (OR 1.23; 95% CI 1.13 to 1.33; I2 = 69%), assuring confidentiality (OR 1.33; 95% CI 1.24 to 1.42); using first-class outward mailing (OR 1.11; 95% CI 1.02 to 1.21); and when questionnaires originated from a university (OR 1.32; 95% CI 1.13 to 1.54). The odds of response were reduced when the questionnaire included questions of a sensitive nature (OR 0.94; 95% CI 0.88 to 1.00). Electronic We found 88 eligible trials that evaluated over 30 different ways of increasing response to electronic questionnaires. We found substantial heterogeneity amongst trial results in half of the strategies. The odds of response tripled when: using a brief letter rather than a detailed letter (OR 3.26; 95% CI 1.79 to 5.94); and when a picture was included in an email (OR 3.05; 95% CI 1.84 to 5.06; I2 = 19%). The odds of response almost doubled when: using monetary incentives (OR 1.88; 95% CI 1.31 to 2.71; I2 = 79%); and using a more interesting topic (OR 1.85; 95% CI 1.52 to 2.26). The odds of response increased by half when: using non-monetary incentives (OR 1.60; 95% CI 1.25 to 2.05); using shorter e-questionnaires (OR 1.51; 95% CI 1.06 to 2.16; I2 = 94%); and using a more interesting e-questionnaire (OR 1.85; 95% CI 1.52 to 2.26). The odds of response increased by a third when: offering survey results as an incentive (OR 1.36; 95% CI 1.16 to 1.59); using a white background (OR 1.31; 95% CI 1.10 to 1.56); and when stressing the benefits to society of response (OR 1.38; 95% CI 1.07 to 1.78; I2 = 41%). The odds of response also increased with: personalised e-questionnaires (OR 1.24; 95% CI 1.17 to 1.32; I2 = 41%); using a simple header (OR 1.23; 95% CI 1.03 to 1.48); giving a deadline (OR 1.18; 95% CI 1.03 to 1.34); and by giving a longer time estimate for completion (OR 1.25; 95% CI 0.96 to 1.64). The odds of response were reduced when: "Survey" was mentioned in the e-mail subject (OR 0.81; 95% CI 0.67 to 0.97); when the email or the e-questionnaire was from a male investigator, or it included a male signature (OR 0.55; 95% CI 0.38 to 0.80); and by using university sponsorship (OR 0.84; 95%CI 0.69 to 1.01). The odds of response using a postal questionnaire were over twice those using an e-questionnaire (OR 2.33; 95% CI 2.25 to 2.42; I2 = 98%). Response also increased when: providing a choice of response mode (electronic or postal) rather than electronic only (OR 1.76 95% CI 1.67 to 1.85; I2 = 97%); and when administering the e-questionnaire by computer rather than by smartphone (OR 1.62 95% CI 1.36 to 1.94).

AUTHORS' CONCLUSIONS

Researchers using postal and electronic questionnaires can increase response using the strategies shown to be effective in this Cochrane review.

Enclosing a pen in a postal questionnaire follow-up to increase response rate: a study within a trial

Background

Poor response rates to follow-up questionnaires can adversely affect the progress of a randomised controlled trial and the validity of its results. This embedded 'study within a trial' aimed to investigate the impact of including a pen with the postal 3-month questionnaire completed by the trial participants on the response rates to this questionnaire.

Methods

This study was a two-armed randomised controlled trial nested in the Gentle Years Yoga (GYY) trial. Participants in the intervention group of the GYY trial were allocated 1:1 using simple randomisation to either receive a pen (intervention) or no pen with their 3-month questionnaire (control). The primary outcome was the proportion of participants sent a 3-month questionnaire who returned it. Secondary outcomes were time taken to return the questionnaire, proportion of participants sent a reminder to return the questionnaire, and completeness of the questionnaire. Binary outcomes were analysed using logistic regression, time to return by Cox Proportional Hazards regression and number of items completed by linear regression.

Results

There were 111 participants randomised to the pen group and 118 to the no pen group who were sent a 3-month questionnaire. There was no evidence of a difference in return rates between the two groups (pen 107 (96.4%), no pen 117 (99.2%); OR 0.23, 95% CI 0.02 to 2.19, p=0.20). Furthermore, there was no evidence of a difference between the two groups in terms of time to return the questionnaire (HR 0.90, 95% CI 0.69 to 1.18, p=0.47), the proportion of participants sent a reminder (OR 0.85, 95% CI 0.48 to 1.53, p=0.60) nor the number of items completed (mean difference 0.51, 95% CI -0.04 to 1.06, p=0.07).

Conclusion

The inclusion of a pen with the postal 3-month follow-up questionnaire did not have a statistically significant effect on response rate.

Enclosing a pen in a postal questionnaire follow-up to increase response rate: a study within a trial [version 1; peer review: 2 approved]

Background

Poor response rates to follow-up questionnaires can adversely affect the progress of a randomised controlled trial and the validity of its results. This embedded 'study within a trial' aimed to investigate the impact of including a pen with the postal 3-month questionnaire completed by the trial participants on the response rates to this questionnaire.

Methods

This study was a two-armed randomised controlled trial nested in the Gentle Years Yoga (GYY) trial. Participants in the intervention group of the GYY trial were allocated 1:1 using simple randomisation to either receive a pen (intervention) or no pen with their 3-month questionnaire (control). The primary outcome was the proportion of participants sent a 3-month questionnaire who returned it. Secondary outcomes were time taken to return the questionnaire, proportion of participants sent a reminder to return the questionnaire, and completeness of the questionnaire. Binary outcomes were analysed using logistic regression, time to return by Cox Proportional hazards regression and number of items completed by linear regression.

Results

There were 111 participants randomised to the pen group and 118 to the no pen group who were sent a 3-month questionnaire. There was no evidence of a difference in return rates between the two groups (pen 107 (96.4%), no pen 117 (99.2%); OR 0.23, 95% CI 0.02 to 2.19, p=0.20). Furthermore, there was no evidence of a difference between the two groups in terms of time to return the questionnaire (HR 0.90, 95% CI 0.69 to 1.18, p=0.47), the proportion of participants sent a reminder (OR 0.85, 95% CI 0.48 to 1.53, p=0.60) nor the number of items completed (mean difference 0.51, 95% CI-0.04 to 1.06, p=0.07).

Conclusion

The inclusion of a pen with the postal 3-month follow-up questionnaire did not have a statistically significant effect on response rate.

Including a pen and/or cover letter, containing social incentive text, had no effect on questionnaire response rate: a factorial randomised controlled Study within a Trial

Background: Postal questionnaires are frequently used in randomised controlled trials to collect outcome data on participants; however, poor response can introduce bias, affect generalisability and validity, and reduce statistical power. The objective of this study was to assess whether a pen and/or social incentive text cover letter sent with a postal follow-up questionnaire increased response rates in a trial.

Method: A two-by-two factorial randomised controlled trial was embedded within the OTIS host trial. Participants due their 12-month (final) follow-up questionnaire were randomised to be sent: a pen; a social incentive text cover letter; both; or neither. The primary outcome measure was the proportion of participants in each group who returned the questionnaire. Secondary outcomes were: time to return, completeness of the questionnaire, necessity of a reminder letter, and the cost effectiveness.

Results: The overall 12-month questionnaire response rate was 721 out of 755 (95.5%). Neither the pen nor social incentive cover letter had a statistically significant effect on response rate: pen 95.2% vs. no pen 95.8%, adjusted OR 0.90 (95% CI 0.45 to 1.80; p=0.77); social incentive cover letter 95.2% vs. no social incentive cover letter 95.8%, adjusted OR 0.84 (95% CI 0.42 to 1.69, p=0.63). No statistically significant differences were observed between either of the intervention groups on time to response, need for a reminder or completeness. Therefore, neither intervention was cost-effective.

Conclusions: We found no evidence of a difference in response rates associated with the inclusion of a pen and/or social incentive cover letter with the final follow-up postal questionnaire of the host trial. However, when these results are combined with previous SWATs, the meta-analysis evidence remains that including a pen increases response rates. The social incentive cover letter warrants further investigation to determine effectiveness.

Trial registration: ISRCTN22202133 (21st June 2020).

Enclosing a pen to improve response rate to postal questionnaire: an embedded randomised controlled trial

Background: Poor response to questionnaires collecting outcome data in randomised controlled trials (RCTs) can affect the validity of trial results. The aim of this study within a trial (SWAT) was to evaluate the effectiveness of including a pen with a follow-up postal questionnaire on response rate. Methods: A two-armed RCT was embedded within SSHeW (Stopping Slips among Healthcare Workers), a trial of slip-resistant footwear to reduce slips in NHS staff.  Participants were randomised 1:1 to receive a pen or no pen with their follow-up questionnaire. The primary outcome was the proportion of participants who returned the questionnaire. Secondary outcomes were: time to response, completeness of response, and whether a postal reminder notice was required. Data were analysed using logistic regression, linear regression and Cox proportional hazards regression. Results: Overall, 1466 SSHEW trial participants were randomised into the SWAT. In total, 13 withdrew from the host trial before they were due to be sent their follow-up questionnaire, 728 participants received a pen with their questionnaire, and 725 did not receive a pen.  A questionnaire was returned from 67.7% of the pen group and 64.7% of the group who did not receive a pen. There was no significant difference in return rates between the two groups (OR 1.15, 95% CI 0.92 to 1.43, p=0.22), nor level of completeness of the questionnaires (AMD -0.01, 95% CI 0.06 to 0.05, p=0.77).  There was weak evidence of a reduction in the proportion of participants requiring a reminder and in time to response in the pen group. Conclusion: Inclusion of a pen with the follow-up postal questionnaire sent to participants in the SSHeW trial did not statistically significantly increase the response rate. These results add to the body of evidence around improving response rates in trials. Trial registration: ISRCTN 33051393 (for SSHEW). Registered on 14/03/2017.

Strategies to improve retention in randomised trials

BACKGROUND

Poor retention of participants in randomised trials can lead to missing outcome data which can introduce bias and reduce study power, affecting the generalisability, validity and reliability of results. Many strategies are used to improve retention but few have been formally evaluated.

OBJECTIVES

To quantify the effect of strategies to improve retention of participants in randomised trials and to investigate if the effect varied by trial setting.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Scopus, PsycINFO, CINAHL, Web of Science Core Collection (SCI-expanded, SSCI, CPSI-S, CPCI-SSH and ESCI) either directly with a specified search strategy or indirectly through the ORRCA database. We also searched the SWAT repository to identify ongoing or recently completed retention trials. We did our most recent searches in January 2020.

SELECTION CRITERIA

We included eligible randomised or quasi-randomised trials of evaluations of strategies to increase retention that were embedded in 'host' randomised trials from all disease areas and healthcare settings. We excluded studies aiming to increase treatment compliance.

DATA COLLECTION AND ANALYSIS

We extracted data on: the retention strategy being evaluated; location of study; host trial setting; method of randomisation; numbers and proportions in each intervention and comparator group. We used a risk difference (RD) and 95% confidence interval (CI) to estimate the effectiveness of the strategies to improve retention. We assessed heterogeneity between trials. We applied GRADE to determine the certainty of the evidence within each comparison.

MAIN RESULTS

We identified 70 eligible papers that reported data from 81 retention trials. We included 69 studies with more than 100,000 participants in the final meta-analyses, of which 67 studies evaluated interventions aimed at trial participants and two evaluated interventions aimed at trial staff involved in retention. All studies were in health care and most aimed to improve postal questionnaire response. Interventions were categorised into broad comparison groups: Data collection; Participants; Sites and site staff; Central study management; and Study design. These intervention groups consisted of 52 comparisons, none of which were supported by high-certainty evidence as determined by GRADE assessment. There were four comparisons presenting moderate-certainty evidence, three supporting retention (self-sampling kits, monetary reward together with reminder or prenotification and giving a pen at recruitment) and one reducing retention (inclusion of a diary with usual follow-up compared to usual follow-up alone). Of the remaining studies, 20 presented GRADE low-certainty evidence and 28 presented very low-certainty evidence. Our findings do provide a priority list for future replication studies, especially with regard to comparisons that currently rely on a single study.

AUTHORS' CONCLUSIONS

Most of the interventions we identified aimed to improve retention in the form of postal questionnaire response. There were few evaluations of ways to improve participants returning to trial sites for trial follow-up. None of the comparisons are supported by high-certainty evidence. Comparisons in the review where the evidence certainty could be improved with the addition of well-done studies should be the focus for future evaluations.

A Population-Based Mortality Follow-Back Survey Evaluating Good Death for Cancer and Noncancer Patients: A Randomized Feasibility Study

CONTEXT

Evaluation of end-of-life care is a key element in quality improvement, and population-based mortality follow-back designs have been used in several countries. This design was adapted to evaluate a good death in Japan.

OBJECTIVES

This study aimed to explain the scientific background and rationale for assessing the feasibility of a mortality follow-back survey using a randomized design.

DESIGN

We used a cross-sectional questionnaire survey to assess feasibility using response rate, sample representativeness, effect on response rate with two methods, and survey acceptability.

SETTING/PARTICIPANTS

The subjects were 4812 bereaved family members of patients who died from the major five causes of death: cancer, heart disease, cerebrovascular disease, pneumonia, or kidney failure, using mortality data.

RESULTS

Overall, 682 (14.2%) questionnaires could not be delivered, and 2294 (55.5%) family members agreed to participate in the survey. There was little difference in the distribution of characteristics between the study subjects and the full population, and sample representativeness was acceptable. Sending the questionnaire with a pen achieved a higher response rate than without (weighted: 48.2% vs. 40.8%; P < 0.001). In follow-up contact, there was no difference in response rate between resending the questionnaire and a reminder letter alone (weighted: 32.9% vs. 32.4%; P = 0.803). In total, 84.8% (weighted) of the participants agreed with improving quality of care through this kind of survey.

CONCLUSION

This study demonstrated the feasibility of conducting a population-based mortality follow-back survey using a randomized design. An attached pen with the questionnaire was effective in improving the response rate.

Using pens as an incentive for trial recruitment of older adults: An embedded randomised controlled trial

Background: Meeting recruitment targets for randomised controlled trials is challenging.  This trial evaluated the effectiveness of including a pen within the trial invitation pack on the recruitment of older adults into a randomised controlled trial. Methods: This trial was embedded within the Occupational Therapist Intervention Study, a falls-prevention randomised controlled trial.  Potential participants (n = 1862), who were posted an invitation pack from two General Practitioner practices, were randomised to either not receive a pen (n = 1295) or receive a pen (n = 648) with their invitation pack, using a 2:1 ratio.  The primary outcome was the likelihood of being randomised, and therefore fully recruited, to the host trial.  To be randomised to the host trial, participants had to: return a consent form and screening form; be eligible on their screening form; and return a baseline questionnaire and a monthly falls calendar.  Secondary outcomes were: the likelihood of returning (and time to return) a screening form; being eligible for the host trial; and remaining in the trial for at least 3 months. Results: The likelihood of being randomised to the host trial did not differ between the pen group (4.5%) and no pen group (4.3%; odds ratio 1.04; 95% confidence interval: 0.65 to 1.67; p = 0.86).  There were marginal differences in secondary outcomes in favour of the pen group, particularly in screening form return rates, though these differences were not statistically significant. Conclusion: Pens may not be an effective incentive for the recruitment of older adults into randomised controlled trials, though future trials are required. Registration: ISRCTN22202133; SWAT 37.

Most response-inducing strategies do not increase participation in observational studies: a systematic review and meta-analysis

OBJECTIVES

To evaluate response-inducing strategies for observational studies using health-related questionnaires or interviews.

STUDY DESIGN AND SETTING

We searched PubMed, EMBASE, CINAHL, PsycINFO, and Web of Science up to December 28, 2017. Studies evaluating the effect of a response-inducing strategy on participation rates of observational studies were included. For each strategy, we estimated pooled response ratios with 95% confidence intervals (CIs) in a Hartung-Knapp/Sidik-Jonkman random effects model with the final participation rate as outcome, stratified for type of participants and method of data collection.

RESULTS

The search yielded 168 eligible studies involving 367,616 potential participants and 33 strategies. Among patients, response-inducing strategies for paper-based questionnaires included unconditional monetary incentives (response ratio 1.15; 95% CI 1.09-1.21) and shorter questionnaires (1.04; 1.02-1.06). Among nonpatients, a personalized mode of delivery (1.47; 1.24-1.74), more expensive mailing type (1.25; 1.00-1.56), unconditional monetary incentives (1.24; 1.12-1.38), prenotification (1.12; 1.03-1.22), unconditional scratch lottery tickets (1.09; 1.01-1.18), and shorter questionnaires (1.06; 1.02-1.11) increased response rates to paper-based questionnaires. For Web-based questionnaires and interviews among nonpatients, response rates were increased by conditional lottery tickets (1.17; 1.02-1.34) and conditional monetary incentives (1.39; 1.01-1.91), respectively.

CONCLUSION

Although the majority of strategies evaluated were unsuccessful, some may increase response rates to observational studies, particularly among nonpatients.

Best practice guidance for the use of strategies to improve retention in randomized trials developed from two consensus workshops

Objectives

To develop best practice guidance for the use of retention strategies in randomized clinical trials (RCTs).

Study Design and Setting

Consensus development workshops conducted at two UK Clinical Trials Units. Sixty-six statisticians, clinicians, RCT coordinators, research scientists, research assistants, and data managers associated with RCTs participated. The consensus development workshops were based on the consensus development conference method used to develop best practice for treatment of medical conditions. Workshops commenced with a presentation of the evidence for incentives, communication, questionnaire format, behavioral, case management, and methodological retention strategies identified by a Cochrane review and associated qualitative study. Three simultaneous group discussions followed focused on (1) how convinced the workshop participants were by the evidence for retention strategies, (2) barriers to the use of effective retention strategies, (3) types of RCT follow-up that retention strategies could be used for, and (4) strategies for future research. Summaries of each group discussion were fed back to the workshop. Coded content for both workshops was compared for agreement and disagreement. Agreed consensus on best practice guidance for retention was identified.

Results

Workshop participants agreed best practice guidance for the use of small financial incentives to improve response to postal questionnaires in RCTs. Use of second-class post was thought to be adequate for postal communication with RCT participants. The most relevant validated questionnaire was considered best practice for collecting RCT data. Barriers identified for the use of effective retention strategies were: the small improvements seen in questionnaire response for the addition of monetary incentives, and perceptions among trialists that some communication strategies are outdated. Furthermore, there was resistance to change existing retention practices thought to be effective. Face-to-face and electronic follow-up technologies were identified as retention strategies for further research.

Conclusions

We developed best practice guidance for the use of retention strategies in RCTs and identified potential barriers to the use of effective strategies. The extent of agreement on best practice is limited by the variability in the currently available evidence. This guidance will need updating as new retention strategies are developed and evaluated.

The effect of postal questionnaire burden on response rate and answer patterns following admission to intensive care: a randomised controlled trial

Background

The effects of postal questionnaire burden on return rates and answers given are unclear following treatment on an intensive care unit (ICU). We aimed to establish the effects of different postal questionnaire burdens on return rates and answers given.

Methods

Design: A parallel group randomised controlled trial. We assigned patients by computer-based randomisation to one of two questionnaire packs (Group A and Group B).

Setting: Patients from 26 ICUs in the United Kingdom.

Inclusion criteria: Patients who had received at least 24 h of level 3 care and were 16 years of age or older. Patients did not know that there were different questionnaire burdens. The study included 18,490 patients. 12,170 were eligible to be sent a questionnaire pack at 3 months. We sent 12,105 questionnaires (6112 to group A and 5993 to group B).

Interventions: The Group A pack contained demographic and EuroQol group 5 Dimensions 3 level (EQ-5D-3 L) questionnaires, making four questionnaire pages. The Group B pack also contained the Hospital Anxiety and Depression Score (HADS) and the Post-Traumatic Stress Disorder Check List-Civilian (PCL-C) questionnaires, making eight questionnaire pages in total.

Main outcome measure: Questionnaire return rate 3 months after ICU discharge by group.

Results

In group A, 2466/6112 (40.3%) participants responded at 3 months. In group B 2315/ 5993 (38.6%) participants responded (difference 1.7% CI for difference 0–3.5% p = 0.053).

Group A reported better functionality than group B in the EQ-5D-3 L mobility (41% versus 37% reporting no problems p = 0.003) and anxiety/depression (59% versus 55% reporting no problems p = 0.017) domains.

Conclusions

In survivors of intensive care, questionnaire burden had no effect on return rates. However, questionnaire burden affected answers to the same questionnaire (EQ-5D-3 L).

Trial registration

ISRCTN69112866 (assigned 02/05/2006).

Electronic supplementary material

The online version of this article (doi:10.1186/s12874-017-0319-3) contains supplementary material, which is available to authorized users.

Enclosing a pen reduced time to response to questionnaire mailings

OBJECTIVES

To assess the effectiveness of including a pen in postal questionnaires on response rate, necessity of reminders, time to response, and completeness of response to the primary outcome question (POQ).

STUDY DESIGN AND SETTING

A two-arm randomized controlled trial (RCT) embedded within the screening of older women for prevention of fracture trial (SCOOP). Women, aged 70-75 years, were randomized to receive a pen with their questionnaire (n = 3,826) or to receive the questionnaire alone (n = 3,829). The results were combined with another embedded RCT in a meta-analysis.

RESULTS

A response rate of 92.4% was observed in the pen group compared with 91.3% in the control group (odds ratio [OR] = 1.16; 95% confidence interval [CI]: 0.98, 1.37; P = 0.08). There was a difference in reminders required (OR = 0.88; 95% CI: 0.79, 0.98; P = 0.02), time to response (hazard ratio = 1.06; 95% CI: 1.01, 1.11; P = 0.01) and some difference in the completeness of response to the POQ (OR = 1.18; 95% CI: 1.00, 1.39; P = 0.05). The pooled OR from the meta-analysis for response rate was 1.21 (95% CI: 1.05, 1.39; P = 0.01).

CONCLUSION

Inclusion of a pen with postal questionnaires potentially has a positive impact on response rates and the number of reminders required. There may be some reduction in time to response. Studies of different participant groups are needed to test the effectiveness over more diverse populations.

SMS text pre-notification and delivery of reminder e-mails to increase response rates to postal questionnaires in the SUSPEND trial: a factorial design, randomised controlled trial

BACKGROUND

Patient-reported outcomes are vital in informing randomised controlled trials (RCTs) and health-care interventions and policies from the patient's perspective. However, participant non-response may introduce bias and can affect the generalisability of the trial. This study evaluates two interventions aimed at increasing response rates to postal questionnaires within a large, UK-wide RCT: pre-notification via short messenger service (SMS) text prior to sending the initial mailing of trial questionnaires versus no pre-notification; for non-responders to the initial mailing of the questionnaires, an e-mail reminder (containing a hyperlink to complete the questionnaire online) versus a postal reminder.

METHODS

This study is a 2 × 2 partial factorial design RCT nested within an RCT of medical expulsive therapy for ureteric stone disease. Participants who supplied a mobile telephone number were randomly assigned to receive an SMS text pre-notification of questionnaire delivery or no pre-notification. Those who supplied an e-mail address were randomly assigned to receive a questionnaire reminder by e-mail or post. Participants could be randomly assigned to the pre-notification comparison or the reminder comparison or both. The primary outcome measure was response rate at each questionnaire time point.

RESULTS

Four hundred eighteen participants were randomly assigned to the SMS pre-notification comparison (80% were male, and the mean age was 41 years with a standard deviation (SD) of 11.1). The intervention had no effect on response rate at either questionnaire time point. In subgroup analyses, SMS pre-notification increased response rates in women but only at the first questionnaire time point. One hundred nineteen participants were randomly assigned to the reminder comparison (80% were male, and the mean age was 42 years with an SD of 12.1). There was no difference in response rate in those who received an e-mail reminder compared with those who received a postal reminder.

CONCLUSIONS

SMS text pre-notification of questionnaire delivery and email delivery of questionnaire reminders did not improve response rates. There was some evidence to suggest that SMS text pre-notification may be effective in women, and further studies to investigate this may be warranted. E-mail reminders for participants to return their postal questionnaire could be advantageous given that response rates were similar following either type of reminder and the low cost of delivering an e-mail compared with a postal reminder. This is a substudy of the SUSPEND trial (ISCTRN69423238) (18 Nov. 2010).

Survey of the UK veterinary profession: common species and conditions nominated by veterinarians in practice

The practice of evidence-based veterinary medicine involves the utilisation of scientific evidence for clinical decision making. To enable this, research topics pertinent to clinical practice need to be identified, and veterinary clinicians are best placed to do this. The main aim of this study was to describe the veterinary population, the common species and conditions veterinary clinicians nominated they saw in practice and how much information clinicians perceived was available in the literature for these. A questionnaire was distributed to all Royal College of Veterinary Surgeons registered veterinarians agreeing to be contacted for research purposes (n=14,532). A useable response rate of 33 per cent (4842/14,532) was achieved. The most commonly seen species reported by vets were dogs, cats and rabbits followed by equines and cattle. Overall, skin conditions were most commonly mentioned for small animals, musculoskeletal conditions for equines and reproduction conditions for production animals. Veterinary clinicians perceived there was a higher level of information available in the literature for conditions in dogs, cattle and equines and lower levels for rabbits and guinea pigs. The results from this study can be used to help define the research needs of the profession to aid the incorporation of evidence in veterinary practice.

Strategies to improve retention in randomised trials: a Cochrane systematic review and meta-analysis

OBJECTIVE

To quantify the effect of strategies to improve retention in randomised trials.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Sources searched: MEDLINE, EMBASE, PsycINFO, DARE, CENTRAL, CINAHL, C2-SPECTR, ERIC, PreMEDLINE, Cochrane Methodology Register, Current Controlled Trials metaRegister, WHO trials platform, Society for Clinical Trials (SCT) conference proceedings and a survey of all UK clinical trial research units.

REVIEW METHODS

Included trials were randomised evaluations of strategies to improve retention embedded within host randomised trials. The primary outcome was retention of trial participants. Data from trials were pooled using the fixed-effect model. Subgroup analyses were used to explore the heterogeneity and to determine whether there were any differences in effect by the type of strategy.

RESULTS

38 retention trials were identified. Six broad types of strategies were evaluated. Strategies that increased postal questionnaire responses were: adding, that is, giving a monetary incentive (RR 1.18; 95% CI 1.09 to 1.28) and higher valued incentives (RR 1.12; 95% CI 1.04 to 1.22). Offering a monetary incentive, that is, an incentive given on receipt of a completed questionnaire, also increased electronic questionnaire response (RR 1.25; 95% CI 1.14 to 1.38). The evidence for shorter questionnaires (RR 1.04; 95% CI 1.00 to 1.08) and questionnaires relevant to the disease/condition (RR 1.07; 95% CI 1.01 to 1.14) is less clear. On the basis of the results of single trials, the following strategies appeared effective at increasing questionnaire response: recorded delivery of questionnaires (RR 2.08; 95% CI 1.11 to 3.87); a 'package' of postal communication strategies (RR 1.43; 95% CI 1.22 to 1.67) and an open trial design (RR 1.37; 95% CI 1.16 to 1.63). There is no good evidence that the following strategies impact on trial response/retention: adding a non-monetary incentive (RR=1.00; 95% CI 0.98 to 1.02); offering a non-monetary incentive (RR=0.99; 95% CI 0.95 to 1.03); 'enhanced' letters (RR=1.01; 95% CI 0.97 to 1.05); monetary incentives compared with offering prize draw entry (RR=1.04; 95% CI 0.91 to 1.19); priority postal delivery (RR=1.02; 95% CI 0.95 to 1.09); behavioural motivational strategies (RR=1.08; 95% CI 0.93 to 1.24); additional reminders to participants (RR=1.03; 95% CI 0.99 to 1.06) and questionnaire question order (RR=1.00, 0.97 to 1.02). Also based on single trials, these strategies do not appear effective: a telephone survey compared with a monetary incentive plus questionnaire (RR=1.08; 95% CI 0.94 to 1.24); offering a charity donation (RR=1.02, 95% CI 0.78 to 1.32); sending sites reminders (RR=0.96; 95% CI 0.83 to 1.11); sending questionnaires early (RR=1.10; 95% CI 0.96 to 1.26); longer and clearer questionnaires (RR=1.01, 0.95 to 1.07) and participant case management by trial assistants (RR=1.00; 95% CI 0.97 to 1.04).

CONCLUSIONS

Most of the trials evaluated questionnaire response rather than ways to improve participants return to site for follow-up. Monetary incentives and offers of monetary incentives increase postal and electronic questionnaire response. Some strategies need further evaluation. Application of these results would depend on trial context and follow-up procedures.

Strategies to improve retention in randomised trials

BACKGROUND

Loss to follow-up from randomised trials can introduce bias and reduce study power, affecting the generalisability, validity and reliability of results. Many strategies are used to reduce loss to follow-up and improve retention but few have been formally evaluated.

OBJECTIVES

To quantify the effect of strategies to improve retention on the proportion of participants retained in randomised trials and to investigate if the effect varied by trial strategy and trial setting.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PreMEDLINE, EMBASE, PsycINFO, DARE, CINAHL, Campbell Collaboration's Social, Psychological, Educational and Criminological Trials Register, and ERIC. We handsearched conference proceedings and publication reference lists for eligible retention trials. We also surveyed all UK Clinical Trials Units to identify further studies.

SELECTION CRITERIA

We included eligible retention trials of randomised or quasi-randomised evaluations of strategies to increase retention that were embedded in 'host' randomised trials from all disease areas and healthcare settings. We excluded studies aiming to increase treatment compliance.

DATA COLLECTION AND ANALYSIS

We contacted authors to supplement or confirm data that we had extracted. For retention trials, we recorded data on the method of randomisation, type of strategy evaluated, comparator, primary outcome, planned sample size, numbers randomised and numbers retained. We used risk ratios (RR) to evaluate the effectiveness of the addition of strategies to improve retention. We assessed heterogeneity between trials using the Chi(2) and I(2) statistics. For main trials that hosted retention trials, we extracted data on disease area, intervention, population, healthcare setting, sequence generation and allocation concealment.

MAIN RESULTS

We identified 38 eligible retention trials. Included trials evaluated six broad types of strategies to improve retention. These were incentives, communication strategies, new questionnaire format, participant case management, behavioural and methodological interventions. For 34 of the included trials, retention was response to postal and electronic questionnaires with or without medical test kits. For four trials, retention was the number of participants remaining in the trial. Included trials were conducted across a spectrum of disease areas, countries, healthcare and community settings. Strategies that improved trial retention were addition of monetary incentives compared with no incentive for return of trial-related postal questionnaires (RR 1.18; 95% CI 1.09 to 1.28, P value < 0.0001), addition of an offer of monetary incentive compared with no offer for return of electronic questionnaires (RR 1.25; 95% CI 1.14 to 1.38, P value < 0.00001) and an offer of a GBP20 voucher compared with GBP10 for return of postal questionnaires and biomedical test kits (RR 1.12; 95% CI 1.04 to 1.22, P value < 0.005). The evidence that shorter questionnaires are better than longer questionnaires was unclear (RR 1.04; 95% CI 1.00 to 1.08, P value = 0.07) and the evidence for questionnaires relevant to the disease/condition was also unclear (RR 1.07; 95% CI 1.01 to 1.14). Although each was based on the results of a single trial, recorded delivery of questionnaires seemed to be more effective than telephone reminders (RR 2.08; 95% CI 1.11 to 3.87, P value = 0.02) and a 'package' of postal communication strategies with reminder letters appeared to be better than standard procedures (RR 1.43; 95% CI 1.22 to 1.67, P value < 0.0001). An open trial design also appeared more effective than a blind trial design for return of questionnaires in one fracture prevention trial (RR 1.37; 95% CI 1.16 to 1.63, P value = 0.0003).There was no good evidence that the addition of a non-monetary incentive, an offer of a non-monetary incentive, 'enhanced' letters, letters delivered by priority post, additional reminders, or questionnaire question order either increased or decreased trial questionnaire response/retention. There was also no evidence that a telephone survey was either more or less effective than a monetary incentive and a questionnaire. As our analyses are based on single trials, the effect on questionnaire response of using offers of charity donations, sending reminders to trial sites and when a questionnaire is sent, may need further evaluation. Case management and behavioural strategies used for trial retention may also warrant further evaluation.

AUTHORS' CONCLUSIONS

Most of the retention trials that we identified evaluated questionnaire response. There were few evaluations of ways to improve participants returning to trial sites for trial follow-up. Monetary incentives and offers of monetary incentives increased postal and electronic questionnaire response. Some other strategies evaluated in single trials looked promising but need further evaluation. Application of the findings of this review would depend on trial setting, population, disease area, data collection and follow-up procedures.

Prenotification had no additional effect on the response rate and survey quality: a randomized trial

OBJECTIVES

To determine the effect of prenotification package on survey quality, including response rates, response time, percentage of nonresponse items, and cost.

STUDY DESIGN AND SETTING

Participants were randomized into two groups. In the first round mailing, participants in prenotification group received a prenotification package, whereas direct questionnaire mailing group participants received a questionnaire with prepaid return envelope only. In the second round mailing, both groups received the questionnaires. The trial was integrated into a study among 35-65-year-old female nurses in Hong Kong.

RESULTS

A total of 367 nurses were included in the trial. A total of 362 mails were successfully delivered. The initial response rate in the first round mailing were 8.79% and 8.89% for prenotification and direct questionnaire mailing groups, respectively. After the second round mailing, the final response rate in prenotification and direct questionnaire mailing groups were 17.58% and 17.22%, respectively; no significant difference was found between the groups. There were no differences with respect to percentage of nonresponse items or response time, but the cost of prenotification group was HK$ 15.11 per response higher than direct mailing group.

CONCLUSION

Prenotification had no additional effect on the response rate and other survey quality compared with direct questionnaire mailing in a Hong Kong population.

After-effects reported by women having follow-up cervical cytology tests in primary care: a cohort study within the TOMBOLA trial

BACKGROUND

Although it is recognised that some women experience pain or bleeding during a cervical cytology test, few studies have quantified physical after-effects of these tests.

AIM

To investigate the frequency, severity, and duration of after-effects in women undergoing follow-up cervical cytology tests, and to identify subgroups with higher frequencies in Grampian, Tayside, and Nottingham.

DESIGN

Cohort study nested with a multi-centre individually randomised controlled trial.

METHOD

The cohort included 1120 women, aged 20-59 years, with low-grade abnormal cervical cytology who completed a baseline sociodemographic questionnaire and had a follow-up cervical cytology test in primary care 6 months later. Six weeks after this test, women completed a postal questionnaire on pain, bleeding, and discharge experienced after the test, including duration and severity. The adjusted prevalence of each after-effect was computed using logistic regression.

RESULTS

A total of 884 women (79%) completed the after-effects questionnaire; 30% of women experienced one or more after-effect: 15% reported pain, 16% bleeding, and 7% discharge. The duration of discharge was ≤2 days for 66%, 3-6 days for 22%, and ≥7 days for 11% of women. Pain or bleeding lasted ≤2 days in more than 80% of women. Severe after-effects were reported by <1% of women. The prevalence of pain decreased with increasing age. Bleeding was more frequent among nulliparous women. Discharge was more common among oral contraceptive users.

CONCLUSION

Pain, bleeding, and discharge are not uncommon in women having follow-up cervical cytology tests. Informing women about possible after-effects could better prepare them and provide reassurance, thereby minimising potential non-adherence with follow-up or non-participation with screening in the future.

Study on occupational allergy risks (SOLAR II) in Germany: design and methods

BACKGROUND

SOLAR II is the 2nd follow-up of a population-based cohort study that follows the participants of ISAAC Phase Two recruited in Munich and Dresden in 1995/6. A first follow-up study was conducted 2002 and 2003 (SOLAR I). The aims of SOLAR II were to investigate the course of atopic diseases over puberty taking environmental and occupational risk factors into account. This paper describes the methods of the 2nd follow-up carried out from 2007 to 2009 and the challenges we faced while studying a population-based cohort of young adults.

METHODS

Wherever possible, the same questionnaire instruments were used throughout the studies. They included questions on respiratory and allergic diseases, domestic and occupational exposure and work related stress. Furthermore, clinical examinations including skin prick tests, spirometry and bronchial challenge with methacholine, exhaled nitric oxide (FeNO) and blood samples were employed at baseline and 2nd follow-up. As information from three studies was available, multiple imputation could be used to handle missing data.

RESULTS

Of the 3053 SOLAR I study participants who had agreed to be contacted again, about 50% had moved in the meantime and had to be traced using phone directories and the German population registries. Overall, 2904 of these participants could be contacted on average five years after the first follow-up. From this group, 2051 subjects (71%) completed the questionnaire they received via mail. Of these, 57% participated at least in some parts of the clinical examinations. Challenges faced included the high mobility of this age group. Time constraints and limited interest in the study were substantial. Analysing the results, selection bias had to be considered as questionnaire responders (54%) and those participating in the clinical part of the study (63%) were more likely to have a high parental level of education compared to non-participants (42%). Similarly, a higher prevalence of parental atopy (e.g. allergic rhinitis) at baseline was found for participants in the questionnaire part (22%) and those participating in the clinical part of the study (27%) compared to non-participants (11%).

CONCLUSIONS

In conclusion, a 12-year follow-up from childhood to adulthood is feasible resulting in a response of 32% of the baseline population. However, our experience shows that researchers need to allocate more time to the field work when studying young adults compared to other populations.

Exploring the facilitators and barriers to engagement in physical activity for people with multiple sclerosis

PURPOSE

To explore the relationship that cognitive behavioural and other previously identified variables have with physical activity engagement in people with multiple sclerosis (MS).

METHODS

This study adopted a cross-sectional questionnaire design. Participants were 282 individuals with MS. Outcome measures included the Physical Activity Disability Survey--Revised, Cognitive and Behavioural Responses to Symptoms Questionnaire, Barriers to Health Promoting Activities for Disabled Persons Scale, Multiple Sclerosis Self-efficacy Scale, Self-Efficacy for Chronic Diseases Scales and Chalder Fatigue Questionnaire.

RESULTS

Multivariable stepwise regression analyses found that greater self-efficacy, greater reported mental fatigue and lower number of perceived barriers to physical activity accounted for a significant proportion of variance in physical activity behaviour, over that accounted for by illness-related variables. Although fear-avoidance beliefs accounted for a significant proportion of variance in the initial analyses, its effect was explained by other factors in the final multivariable analyses.

CONCLUSIONS

Self-efficacy, mental fatigue and perceived barriers to physical activity are potentially modifiable variables which could be incorporated into interventions designed to improve physical activity engagement. Future research should explore whether a measurement tool tailored to capture beliefs about physical activity identified by people with MS would better predict participation in physical activity.

Duration of conjunctival redness following adult strabismus surgery

PURPOSE

To determine the duration of postoperative conjunctival injection following strabismus surgery and to assess how this is affected by previous extraocular muscle surgery. This would improve preoperative counseling of strabismus patients.

METHODS

Subjective evaluation of conjunctival redness based on patient questionnaire response.

RESULTS

Fifty-three patients returned completed questionnaires. A total of 93 muscles were operated on. Of these, 46 had not undergone previous operations; 47 had. Previously unoperated eyes remained red for a median duration of 9.5 weeks; reoperated eyes remained red for a median of 11 weeks. Of the 93 muscles, 50 were sutured with adjustable sutures. These remained red for a median duration of 11 weeks. Muscles tied with nonadjustable sutures remained red for a median of 10 weeks.

CONCLUSIONS

In both previously unoperated and reoperated eyes, conjunctival redness resolved in approximately 10 weeks; adjustable sutures did not alter the duration of redness significantly.

Methods to increase response to postal and electronic questionnaires

BACKGROUND

Postal and electronic questionnaires are widely used for data collection in epidemiological studies but non-response reduces the effective sample size and can introduce bias. Finding ways to increase response to postal and electronic questionnaires would improve the quality of health research.

OBJECTIVES

To identify effective strategies to increase response to postal and electronic questionnaires.

SEARCH STRATEGY

We searched 14 electronic databases to February 2008 and manually searched the reference lists of relevant trials and reviews, and all issues of two journals. We contacted the authors of all trials or reviews to ask about unpublished trials. Where necessary, we also contacted authors to confirm methods of allocation used and to clarify results presented. We assessed the eligibility of each trial using pre-defined criteria.

SELECTION CRITERIA

Randomised controlled trials of methods to increase response to postal or electronic questionnaires.

DATA COLLECTION AND ANALYSIS

We extracted data on the trial participants, the intervention, the number randomised to intervention and comparison groups and allocation concealment. For each strategy, we estimated pooled odds ratios (OR) and 95% confidence intervals (CI) in a random-effects model. We assessed evidence for selection bias using Egger's weighted regression method and Begg's rank correlation test and funnel plot. We assessed heterogeneity among trial odds ratios using a Chi(2) test and the degree of inconsistency between trial results was quantified using the I(2) statistic.

MAIN RESULTS

PostalWe found 481 eligible trials. The trials evaluated 110 different ways of increasing response to postal questionnaires. We found substantial heterogeneity among trial results in half of the strategies. The odds of response were at least doubled using monetary incentives (odds ratio 1.87; 95% CI 1.73 to 2.04; heterogeneity P < 0.00001, I(2) = 84%), recorded delivery (1.76; 95% CI 1.43 to 2.18; P = 0.0001, I(2) = 71%), a teaser on the envelope - e.g. a comment suggesting to participants that they may benefit if they open it (3.08; 95% CI 1.27 to 7.44) and a more interesting questionnaire topic (2.00; 95% CI 1.32 to 3.04; P = 0.06, I(2) = 80%). The odds of response were substantially higher with pre-notification (1.45; 95% CI 1.29 to 1.63; P < 0.00001, I(2) = 89%), follow-up contact (1.35; 95% CI 1.18 to 1.55; P < 0.00001, I(2) = 76%), unconditional incentives (1.61; 1.36 to 1.89; P < 0.00001, I(2) = 88%), shorter questionnaires (1.64; 95% CI 1.43 to 1.87; P < 0.00001, I(2) = 91%), providing a second copy of the questionnaire at follow up (1.46; 95% CI 1.13 to 1.90; P < 0.00001, I(2) = 82%), mentioning an obligation to respond (1.61; 95% CI 1.16 to 2.22; P = 0.98, I(2) = 0%) and university sponsorship (1.32; 95% CI 1.13 to 1.54; P < 0.00001, I(2) = 83%). The odds of response were also increased with non-monetary incentives (1.15; 95% CI 1.08 to 1.22; P < 0.00001, I(2) = 79%), personalised questionnaires (1.14; 95% CI 1.07 to 1.22; P < 0.00001, I(2) = 63%), use of hand-written addresses (1.25; 95% CI 1.08 to 1.45; P = 0.32, I(2) = 14%), use of stamped return envelopes as opposed to franked return envelopes (1.24; 95% CI 1.14 to 1.35; P < 0.00001, I(2) = 69%), an assurance of confidentiality (1.33; 95% CI 1.24 to 1.42) and first class outward mailing (1.11; 95% CI 1.02 to 1.21; P = 0.78, I(2) = 0%). The odds of response were reduced when the questionnaire included questions of a sensitive nature (0.94; 95% CI 0.88 to 1.00; P = 0.51, I(2) = 0%).ElectronicWe found 32 eligible trials. The trials evaluated 27 different ways of increasing response to electronic questionnaires. We found substantial heterogeneity among trial results in half of the strategies. The odds of response were increased by more than a half using non-monetary incentives (1.72; 95% CI 1.09 to 2.72; heterogeneity P < 0.00001, I(2) = 95%), shorter e-questionnaires (1.73; 1.40 to 2.13; P = 0.08, I(2) = 68%), including a statement that others had responded (1.52; 95% CI 1.36 to 1.70), and a more interesting topic (1.85; 95% CI 1.52 to 2.26). The odds of response increased by a third using a lottery with immediate notification of results (1.37; 95% CI 1.13 to 1.65), an offer of survey results (1.36; 95% CI 1.15 to 1.61), and using a white background (1.31; 95% CI 1.10 to 1.56). The odds of response were also increased with personalised e-questionnaires (1.24; 95% CI 1.17 to 1.32; P = 0.07, I(2) = 41%), using a simple header (1.23; 95% CI 1.03 to 1.48), using textual representation of response categories (1.19; 95% CI 1.05 to 1.36), and giving a deadline (1.18; 95% CI 1.03 to 1.34). The odds of response tripled when a picture was included in an e-mail (3.05; 95% CI 1.84 to 5.06; P = 0.27, I(2) = 19%). The odds of response were reduced when "Survey" was mentioned in the e-mail subject line (0.81; 95% CI 0.67 to 0.97; P = 0.33, I(2) = 0%), and when the e-mail included a male signature (0.55; 95% CI 0.38 to 0.80; P = 0.96, I(2) = 0%).

AUTHORS' CONCLUSIONS

Health researchers using postal and electronic questionnaires can increase response using the strategies shown to be effective in this systematic review.

The value and impact of information provided through library services for patient care: developing guidance for best practice

INTRODUCTION

Previous impact tool-kits for UK health libraries required updating to reflect recent evidence and changes in library services. The National Knowledge Service funded development of updated guidance.

METHODS

Survey tools were developed based on previous impact studies and a systematic review. The resulting draft questionnaire survey was tested at four sites, and the interview schedule was investigated in a fifth area. A literature search in ASSIA, Google Scholar, INTUTE, LISA, LISTA, SCIRUS, Social Sciences Citation Index (Web of Knowledge), and the major UK University and National Libraries Catalogue (COPAC), identified ways to improve response rates. Other expert advice contributed to the guidance.

RESULTS

The resulting guidance contains evidence-based advice and a planning pathway for conducting an impact survey as a service audit. The survey tools (critical incident questionnaire and interview schedule) are available online. The evidence-based advice recommends personalizing the request, assuring confidentiality, and using follow-up reminders. Questionnaires should be brief, and small incentives, such as a lottery draw should be considered. Bias is minimized if the survey is conducted and analysed by independent researchers.

CONCLUSION

The guidance is a starting point for a pragmatic survey to assess the impact of health library services.

Questionnaire order significantly increased response to a postal survey sent to primary care physicians

OBJECTIVE

Primary care physicians are increasingly being asked to participate in postal surveys. Difficulties in achieving adequate response rates among physicians have been reported. We investigated the effect of two low-cost interventions on response to a primary care physician postal questionnaire.

STUDY DESIGN AND SETTING

A 2x2 factorial trial was developed within the context of a national survey assessing views and practices of physicians regarding prostate-specific antigen testing. We evaluated questionnaire order (version 1: demographics first, version 2: topic-specific questions first) and written precontact. A national database of primary care physicians was compiled. One thousand five hundred ninety-nine physicians were randomly selected, stratified by health board, and randomized.

RESULTS

47.9% of eligible physicians completed a questionnaire. There was a statistically significant 5.1% higher response rate among physicians receiving version 1 of the questionnaire than those receiving version 2 (50.6% vs. 45.4%, P=0.05); the adjusted odds of response were significantly raised (odds ratio=1.24; 95% confidence interval=1.01-1.54). Precontact resulted in a nonsignificant 3.6% increase in response (49.8% vs. 46.2%; P=0.16). The interventions did not interact.

CONCLUSION

Ordering questionnaires with general questions first can significantly increase response rates, whereas precontact can achieve a modest increase. These strategies may enhance response while adding little to the cost of a physician survey.

Health related quality of life in patients with dystonia and their caregivers in New Zealand and Australia

Health Related Quality of Life (HRQL) was assessed by the SF-36 in a group of patients with dystonia in New Zealand and Australia. The caregivers of these people were also asked to participate. Low scores from the SF-36 indicate a disability or limitation in HRQL. Compared with the national norms of the respective countries, the participants with dystonia for both countries were significantly lower in the eight dimensions of the SF-36, suggesting that patients with dystonia have lower HRQL compared with their respective national norms without dystonia. In contrast to the patients with dystonia, caregivers did not show lower HRQL scores than their national norms, suggesting that while dystonia affects the HRQL of those with the disorder, their caregivers may be less affected. Descriptive and demographic information were also gathered and are discussed. An important factor that may affect the HRQL of patients with dystonia is the length of time required to be diagnosed in this sample and the number of medical practitioners the patients consulted prior to a confirmed diagnosis.