Diagnostics for Respondent-driven Sampling

Respondent-driven sampling (RDS) is a widely used method for sampling from hard-to-reach human populations, especially populations at higher risk for HIV. Data are collected through peer-referral over social networks. RDS has proven practical for data collection in many difficult settings and is widely used. Inference from RDS data requires many strong assumptions because the sampling design is partially beyond the control of the researcher and partially unobserved. We introduce diagnostic tools for most of these assumptions and apply them in 12 high risk populations. These diagnostics empower researchers to better understand their data and encourage future statistical research on RDS.

Study retention as bias reduction in a hard-to-reach population

Collecting data from hard-to-reach populations is a key challenge for research on poverty and other forms of extreme disadvantage. With data from the Boston Reentry Study (BRS), we document the extreme marginality of released prisoners and the related difficulties of study retention and analysis. Analysis of the BRS data yields three findings. First, released prisoners show high levels of "contact insecurity," correlated with social insecurity, in which residential addresses and contact information change frequently. Second, strategies for data collection are available to sustain very high rates of study participation. Third, survey nonresponse in highly marginal populations is strongly nonignorable, closely related to social and economic vulnerability. The BRS response rate of 94% over a 1-y follow-up period allows analysis of hypothetically high nonresponse rates. In this setting, nonresponse attenuates regression estimates in analyses of housing insecurity, drug use, and unemployment. These results suggest that in the analysis of very poor and disadvantaged populations, methods that maximize study participation reduce bias and yield data that can usefully supplement large-scale household or administrative data collections.

Brief Client-Centered Motivational and Behavioral Intervention to Promote HPV Vaccination in a Hard-to-Reach Population: A Pilot Randomized Controlled Trial

Objective To evaluate the impact of a client-centered behavioral intervention (Brief Negotiated Interviewing) on mothers' human papillomavirus (HPV) vaccine knowledge and vaccination initiation for their adolescent daughters. Methods We randomized mothers to intervention (n = 100) and control (n = 100) groups, and followed them over 12 months. Electronic medical records were reviewed to determine vaccination status. The primary outcome was receipt of the first vaccine. The secondary outcome was HPV vaccine knowledge among mothers. Results Brief Negotiated Interviewing intervention mothers demonstrated increased knowledge about HPV (pre/post mean score of 5 to 10 out of a possible 11; P < .001) and significantly higher mean knowledge scores (10 vs 6, P < .001) than control mothers. However, initiation and completion rates of the vaccine were not significantly different between groups. Conclusions Increasing HPV vaccine knowledge did not translate into increased vaccine uptake or completion of vaccination series. Future intervention must explore vaccine reminders to increase HPV vaccination rates.

Strategies used to engage hard-to-reach populations in childhood disability research: a scoping review

PURPOSE

We completed a scoping review to: (1) identify strategies that have been used to engage hard-to-reach populations in childhood disability research, and (2) synthesize information as to whether and how these strategies were evaluated.

METHODS

Systematic search of six electronic databases and grey literature to identify articles published in the last 10 years. Studies published in English, French, and Spanish reporting on strategies used to engage hard-to-reach populations in childhood disability research were eligible for inclusion.

RESULTS

Out of 106 articles selected for full text review, 16 were included. Engagement was more common in earlier stages of research. The populations included in studies were children with disabilities and their parents. Engagement strategies were reported but rarely evaluated. Anecdotal outcomes of engagement were reported in 14/16 studies and included positive outcomes for the children and parents such as empowerment. The challenges with engagement included the increased time needed to engage children with disabilities or their parents.

CONCLUSIONS

Our results can guide others who wish to engage a diverse group of children with disabilities and their parents in research. Research on how to engage other hard-to-reach populations within the childhood disability umbrella and evaluation of engagement strategies and outcomes is needed.IMPLICATIONS FOR REHABILITATION• Service providers should be concerned when the research informing their practices does not include families that represent their clients (e.g., families who are low income, Indigenous, ethnic minority, or LGBTQI parents of children with disabilities).• Strategies used to include children with disabilities in research, such as offering varied response methods that include story telling or photography, may also be used to promote participation in clinical services.• Service providers and teachers may have a role in facilitating the recruitment of 'hard-to-reach' families in research and advising researchers on methods to create a comfortable environment with accessible means of data collection for children with disabilities.

The Healthy Young Men's Study: Sampling Methods to Recruit a Random Cohort of Young Men Who Have Sex with Men

Recruiting a scientifically sound cohort of young men who have sex with men (YMSM) is an enduring research challenge. The few cohort studies that have been conducted to date on YMSM have relied on non-probability sampling methods to construct their cohorts. While these studies have provided valuable information about HIV risk behaviors among YMSM, their generalizability to broader YMSM populations is limited.In this paper the authors describe a venue-based sampling methodology used to recruit a large and diverse cohort of YMSM from public venues in Los Angeles County. Venue-based sampling is a multi-stage, probability sampling design that uses standard outreach techniques and standard survey methods to systematically enumerate, sample, and survey hard-to-reach populations. The study design allowed the authors to estimate individual, familial and interpersonal psychosocial factors associated with HIV risk and health seeking behaviors for a cohort of YMSM with known properties. Study participants completed an extensive baseline survey and over a two year period will complete four follow-up surveys at six-month intervals. The baseline survey was administered in both English and Spanish.

Applications and Recruitment Performance of Web-Based Respondent-Driven Sampling: Scoping Review

BACKGROUND

Web-based respondent-driven sampling is a novel sampling method for the recruitment of participants for generating population estimates, studying social network characteristics, and delivering health interventions. However, the application, barriers and facilitators, and recruitment performance of web-based respondent-driven sampling have not yet been systematically investigated.

OBJECTIVE

Our objectives were to provide an overview of published research using web-based respondent-driven sampling and to investigate factors related to the recruitment performance of web-based respondent-driven sampling.

METHODS

We conducted a scoping review on web-based respondent-driven sampling studies published between 2000 and 2019. We used the process evaluation of complex interventions framework to gain insights into how web-based respondent-driven sampling was implemented, what mechanisms of impact drove recruitment, what the role of context was in the study, and how these components together influenced the recruitment performance of web-based respondent-driven sampling.

RESULTS

We included 18 studies from 8 countries (high- and low-middle income countries), in which web-based respondent-driven sampling was used for making population estimates (n=12), studying social network characteristics (n=3), and delivering health-related interventions (n=3). Studies used web-based respondent-driven sampling to recruit between 19 and 3448 participants from a variety of target populations. Studies differed greatly in the number of seeds recruited, the proportion of successfully recruiting participants, the number of recruitment waves, the type of incentives offered to participants, and the duration of data collection. Studies that recruited relatively more seeds, through online platforms, and with less rigorous selection procedures reported relatively low percentages of successfully recruiting seeds. Studies that did not offer at least one guaranteed material incentive reported relatively fewer waves and lower percentages of successfully recruiting participants. The time of data collection was shortest in studies with university students.

CONCLUSIONS

Web-based respondent-driven sampling can be successfully applied to recruit individuals for making population estimates, studying social network characteristics, and delivering health interventions. In general, seed and peer recruitment may be enhanced by rigorously selecting and motivating seeds, offering at least one guaranteed material incentive, and facilitating adequate recruitment options regarding the target population's online connectedness and communication behavior. Potential trade-offs should be taken into account when implementing web-based respondent-driven sampling, such as having less opportunities to implement rigorous seed selection procedures when recruiting many seeds, as well as issues around online rather than physical participation, such as the risk of cheaters participating repeatedly.

The Experiences of Homeless Youth When Using Strengths Profiling to Identify Their Character Strengths

Individuals, particularly those considered "hard-to-reach," often engage well with assessment tools that involve active dialogue and the co-construction of knowledge. Strengths profiling is one such tool that enables a person-centered and autonomy supportive approach to the identification of character strengths. Strength profiling is an adaptation of performance profiling used in sport psychology, which has not yet been utilized in broader psychological research or clinical practice. Supporting an individual by raising awareness of their personal character strengths is an effective and growing mechanism for promoting psychological well-being. Strengths profiling involves several stages of exploring, defining, and assessing character strengths, leading to the identification of signature strengths and goals for future development. Informed by personal construct theory, the present study explored the experiences of homeless young people living in sheltered accommodation (N = 116), when using strengths profiling at the start and end of a 10-week, strengths-based intervention. Mixed-method data was obtained from the strengths profiles, questionnaires measuring resilience, self-worth, and well-being, and diary entries. Findings revealed a rich array of character strength terminology and individual meanings. Participants found strengths profiling to be highly engaging, particularly due to their active role in strength identification, which prompted interesting and meaningful reflections on character strengths that were pertinent to them. Participants felt their signature strengths were vital protective factors within their lives and strengths profiles were correlated with resilience, self-worth, and well-being. Character strengths and resilience were also significantly and meaningfully improved pre/post-intervention, providing support for the use of strengths profiling as a tool for monitoring change in character strength perceptions. Overall, this study demonstrates the utility and versatility of strengths profiling as a new method in the discipline of positive psychology and strengths-based research and applied practice.

Competing subsistence needs are associated with retention in care and detectable viral load among people living with HIV

Competing priorities between subsistence needs and health care may interfere with HIV health. Longitudinal data from the Los Angeles-based HIV Outreach Initiative were analyzed to examine the association between competing subsistence needs and indicators of poor retention-in-care among hard-to-reach people with HIV. Sacrificing basic needs for health care in the previous six months was associated with a 1.55 times greater incidence of missed appointments (95% CI 1.17, 2.05), 2.32 times greater incidence of emergency department visits (95% CI 1.39, 3.87), 3.66 times greater incidence of not receiving ART if CD4 < 350 (95% CI 1.60, 8.37), and 1.35 times greater incidence of detectable viral load (95% CI 1.07, 1.70) (all p < 0.01). Among hard-to-reach PLHIV, sacrificing basic needs for health care delineates a population with exceptional vulnerability to poor outcomes along the HIV treatment cascade. Efforts to identify and reduce competing needs for this population are crucial to HIV health outcomes.

LATENT DEMOGRAPHIC PROFILE ESTIMATION IN HARD-TO-REACH GROUPS

The sampling frame in most social science surveys excludes members of certain groups, known as hard-to-reach groups. These groups, or sub-populations, may be difficult to access (the homeless, e.g.), camouflaged by stigma (individuals with HIV/AIDS), or both (commercial sex workers). Even basic demographic information about these groups is typically unknown, especially in many developing nations. We present statistical models which leverage social network structure to estimate demographic characteristics of these subpopulations using Aggregated relational data (ARD), or questions of the form "How many X's do you know?" Unlike other network-based techniques for reaching these groups, ARD require no special sampling strategy and are easily incorporated into standard surveys. ARD also do not require respondents to reveal their own group membership. We propose a Bayesian hierarchical model for estimating the demographic characteristics of hard-to-reach groups, or latent demographic profiles, using ARD. We propose two estimation techniques. First, we propose a Markov-chain Monte Carlo algorithm for existing data or cases where the full posterior distribution is of interest. For cases when new data can be collected, we propose guidelines and, based on these guidelines, propose a simple estimate motivated by a missing data approach. Using data from McCarty et al. [Human Organization60 (2001) 28-39], we estimate the age and gender profiles of six hard-to-reach groups, such as individuals who have HIV, women who were raped, and homeless persons. We also evaluate our simple estimates using simulation studies.

Promoting the Participation of "Hard-to-Reach" Migrant Populations in Qualitative Public Health Research during the COVID-19 Pandemic in Chile

The COVID-19 pandemic has further deepened socioeconomic and health inequities worldwide, especially among populations experiencing social vulnerability, such as international migrants. Sustained lockdowns and social distancing have raised challenges to conducting public health research with hard-to-reach populations. This study aims at exploring strategies to recruit "hard-to-reach" international migrants for qualitative public health research during the pandemic in Chile, based on the authors' experience. A retrospective qualitative evaluation process was carried out on the recruitment processes of three qualitative research projects focused on international migrants in Chile. All projects were implemented during the COVID-19 pandemic, demanding complementary and flexible strategies: (i) social media; (ii) snowball sampling; (iii) referrals from social workers and pro-migrant and migrant-led organizations; (iv) vaccination centers and healthcare centers; and (v) community-based recruitment. The strategies are qualitatively evaluated around seven emerging qualitative categories: (i) feasibility during lockdown periods; (ii) speed of recruitment; (iii) geographical coverage; (iv) sample diversity; (v) proportion of successful interviews; (vi) ethical considerations; and (vii) cost. Engaging hard-to-reach international migrants in public health research during the pandemic required constantly adapting recruitment strategies. Furthermore, relying on strategies that were not only Internet-based promoted the participation of populations with limited access to the Internet and low-digital literacy.

Last mile research: a conceptual map

Background: The term 'last mile' has been used across disciplines to refer to populations who are farthest away, most difficult to reach, or last to benefit from a program or service. However, last mile research lacks a shared understanding around its conceptualization.Objectives: This project used a concept mapping process to answer the questions: what is last mile research in global health and, how can it be used to make positive change for health equity in the last mile?Methods: Between July and December 2019, a five-stage concept mapping exercise was undertaken using online concept mapping software and an in-person consensus meeting. The stages were: establishment of an expert group and focus prompt; idea generation; sorting and rating; initial analysis and final consensus meeting.Results: A group of 15 health researchers with experience working with populations in last mile contexts and who were based at the Matariki Network institutions of Queen's University, CAN and Dartmouth College, USA took part. The resulting concept map had 64 unique idea statements and the process resulted in a map with five clusters. These included: (1) Last mile populations; (2) Research methods and approaches; (3) Structural and systemic factors; (4) Health system factors, and (5) Broader environmental factors. Central to the map were the ideas of equity, human rights, health systems, and contextual sensitivity.Conclusion: This is the first time 'last mile research' has been the focus of a formal concept mapping exercise. The resulting map showed consensus about who last mile populations are, how research should be undertaken in the last mile and why last mile health disparities exist. The map can be used to inform research training programs, however, repeating this process with researchers and members from different last mile populations would also add further insight.

Recommendations for Performing Internet-Based Research on Sensitive Subject Matter with "Hidden" or Difficult-to-Reach Populations

Since the mid-1990s, the rapidly increasing popularity of the Internet has contributed to a situation in which many men turn to Web sites to find sex partners with whom they can engage in risky behaviors. Scholars only recently began to examine the role of the Internet in harm-seeking and help-seeking behaviors. They are just now beginning to study and understand how to apply public health promotion principles to people using the Internet. Due in part to the relative newness of the Internet on the public health landscape, scholars wishing to conduct research or to implement health promotion programs online should consider a variety of challenges to doing such work-challenges that differ from those typically faced when undertaking similar work in other types of venues offline. The purpose of this article is to address several of these research considerations. In particular, the present authors wish to provide researchers and health care specialists with key considerations when developing their own Internet-based research or health promotion programs. We also wish to furbish readers with some experience-based suggestions about how to avoid the potential pitfalls of conducting Internet-based studies. Moreover, our emphasis is on how to develop such programs when they are targeting hard-to-reach or "hidden" populations and/or when they deal with sensitive subject matter. Recommendations pertaining to the planning, recruitment, implementation, and evaluation stages of doing professional work online are provided.

Examining Men's Experiences of Abuse From a Female Intimate Partner in Four English-Speaking Countries

This qualitative study explores the experiences of men who self-report victimization from a female intimate partner in four English-speaking countries. Forty-one men who reported any type of intimate partner abuse (IPA) from a female partner were recruited via targeted advertising in Australia, Canada, the United Kingdom, and the United States. Twelve online focus groups were conducted across countries using a phenomenologically informed design. Thematic analysis was carried out from an inductive and realist epistemological position and themes identified at a semantic level. This approach was taken to directly reflect the men's experiences and perspectives, ensuring the voices of this hard-to-reach and overlooked population were heard. Three themes were identified across the countries: an imbalanced experience of harm; living with sustained abuse; and knowledge is power for men experiencing IPA. It was found that most participants underwent physical harm in the context of coercive control and experienced abuse over long periods of time. They were slow to recognize the magnitude of their partners' behavior and act upon it for a range of reasons that are described in detail. In addition, promoting knowledge about the victimization of men by women, using appropriate language and active learning, was found to be important in helping the men gain autonomy and agency to break the pattern of abuse and aid their recovery. The implications of the findings for developing male-friendly IPA policy, practice, and services are discussed, in addition to the need for innovative research methodology to access hard-to-reach populations.

Disseminated tuberculosis and diagnosis delay during the COVID-19 era in a Western European country: a case series analysis

Background

Disseminated tuberculosis is frequently associated with delayed diagnosis and a poorer prognosis.

Objectives

To describe case series of disseminated TB and diagnosis delay in a low TB burden country during the COVID-19 period.

Methodology

We consecutively included all patients with of disseminated TB reported from 2019 to 2021 in the reference hospital of the Northern Crown of the Metropolitan Area of Barcelona. We collected socio-demographic information, clinical, laboratory and radiological findings.

Results

We included all 30 patients reported during the study period-5, 9, and 16 in 2019, 2020, and 2021 respectively-20 (66.7%) of whom were male and whose mean age was 41 years. Twenty-five (83.3%) were of non-EU origin. The most frequent system involvement was central nervous system (N = 8; 26.7%) followed by visceral (N = 7; 23.3%), gastro-intestinal (N = 6, 20.0%), musculoskeletal (N = 5; 16.7%), and pulmonary (N = 4; 13.3%). Hypoalbuminemia and anemia were highly prevalent (72 and 77%). The median of diagnostic delay was 6.5 months (IQR 1.8-30), which was higher among women (36.0 vs. 3.5 months; p = 0.002). Central nervous system involvement and pulmonary involvement were associated with diagnostic delay among women. We recorded 24 cured patients, two deaths, three patients with post-treatment sequelae, and one lost-to-follow up. We observed a clustering effect of patients in low-income neighborhoods (p < 0.001).

Conclusion

There was a substantial delay in the diagnosis of disseminated TB in our study region, which might impacted the prognosis with women affected more negatively. Our results suggest that an increase in the occurrence of disseminated TB set in motion by diagnosis delay may have been a secondary effect of the COVID-19 pandemic.

Lay health advisers: scoping the role and intervention landscape

The use of lay health advisers has become an established approach within public health, in particular for impact on health inequalities and engaging socially excluded groups. Evidence on how differences in terms of the multiple role dimensions impact the outcomes of programs is limited. This creates ambiguity for decision makers on which roles should be implemented in different contexts for different needs. This paper applies realist logic to an inquiry to explore the mechanisms that may operate in lay-led intervention models and understand how, why, and in what respect these lead to particular outcomes. It draws on a project focusing on health-related lifestyle advisers and further insights gained from a subsequent related project about outreach with traveler communities. Analysis highlights multiple and potentially interacting aspects of lay health-adviser roles that may influence their success, including characteristics of lay health advisers, characteristics of target populations, purpose or intent of interventions, and how advice is given. A model is proposed from which to examine the contexts and mechanisms of lay health advisers that may impact outcomes, and is subsequently applied to two examples of reported lay health-adviser interventions. The combination of skills and characteristics of lay health advisers must be considered when planning which interventions might be appropriate when targeting specific needs or target populations. Focus only on the peer/layperson distinction may overlook other potentially important skills and mechanisms of action integral to lay health-adviser roles.

Collecting Data During the COVID-19 Pandemic: Lessons From an In-Person Survey of People Who Use Opioids

OBJECTIVES

In response to the COVID-19 pandemic, much in-person data collection has been suspended or become tele-remote. However, tele-remote methods often exclude marginalized groups, including people who use drugs, many of whom lack the technology to participate. To inform future surveillance and research during the pandemic and other public health disasters, we report methods and lessons learned from an in-person survey of people who use opioids conducted by the New York City Department of Health and Mental Hygiene (DOHMH) during the COVID-19 pandemic.

MATERIALS AND METHODS

This public health surveillance was a component of the Centers for Disease Control and Prevention Overdose Data to Action initiative and aimed to inform overdose prevention efforts. Survey domains inquired about participants' drug use patterns, risk behaviors, overdose history, and service use.

RESULTS

From June 16 through September 9, 2020, DOHMH staff members conducted 329 surveys with participants from 4 syringe service programs (n = 148, 44.9%) and via street intercept (n = 81, 55.1%). To survey participants safely and effectively, it was important to build rapport upfront so that requests to maintain distance were not perceived as stigmatizing. DOHMH staff members offered all participants, regardless of survey eligibility, Narcan and hygiene products, including face masks and soap.

PRACTICE IMPLICATIONS

Surveys administered outdoors during the COVID-19 pandemic should be limited to 30 minutes. Although conducting in-person surveys poses unique challenges, this method should be considered so marginalized populations are included in data collection and public health responses.

Engaging offenders on probation in health research: lessons from the field

Background Offenders on probation are considered to be 'hard to reach' by researchers because probation is a 'closed setting' and engaging offenders in research can be problematic due to issues such as return to custody and chaotic lifestyles. Aim To share learning about the challenges encountered when undertaking research with offenders on probation in the UK, strategies for overcoming them and the implications for research design and outcomes. Discussion The authors identify challenges in gaining and maintaining access; recruitment; ethics; data collection and analysis; and dissemination of findings. They also consider the implications of these challenges for research design and outcomes. Conclusion Engaging offenders in research takes time and effort to gain and maintain access. Researchers need to be persistent and flexible. The potential influence of gatekeepers on recruitment and outcomes is critical and constant communication needs to be maintained. When designing and resourcing projects, researchers must consider the transient nature of the population as well as the need to communicate any potential limits of confidentiality. Implications for practice The lessons learned will be helpful for future research in this field, which is needed to provide data for healthcare commissioners to inform the provision of patient-centred care for this vulnerable and hard-to-reach population.

A Review of Prevalence Estimation Methods for Human Trafficking Populations

Human trafficking has long-lasting implications for the well-being of trafficked people, families, and affected communities. Prevention and intervention efforts, however, have been stymied by a lack of information on the scale and scope of the problem. Because trafficked people are mostly hidden from view, traditional methods of establishing prevalence can be prohibitively expensive in the recruitment, participation, and retention of survey participants. Also, trafficked people are not randomly distributed in the general population. Researchers have therefore begun to apply methods previously used in public health research and other fields on hard-to-reach populations to measure the prevalence of human trafficking. In this topical review, we examine how these prevalence methods used for hard-to-reach populations can be used to measure the prevalence of human trafficking. These methods include network-based approaches, such as respondent-driven sampling and the network scale-up method, and venue-based methods. Respondent-driven sampling is useful, for example, when little information about the trafficked population has been produced and when an adequate sampling frame does not exist. The network scale-up method is unique in that it does not target the hidden population directly. The implications of our work internationally include the need for documenting and validating the various prevalence estimation methods in the United States in a more robust way than was done in existing efforts. In providing this roadmap for estimating the prevalence of human trafficking, our overarching goal is to promote the equitable treatment and overall well-being of the socially disadvantaged populations who disproportionately experience human trafficking.

Engaging hard-to-reach populations in research on health in pregnancy: the value of Boal's simultaneous dramaturgy

Background: Migrant populations are among the hardest to reach for research purposes.Methods: An interdisciplinary research team piloted a modified version of Boal's simultaneous dramaturgy with Roma mothers in Belfast.Results: The technique, based on scripted performances, translations, and discussions, proved effective for engaging with this hard-to-reach population, despite low levels of literacy, high language barriers, and cultural separateness. The approach uncovered attitudes to pregnancy which reinforce health inequalities, and present significant challenges for improving the health of marginalized populations.Conclusions: This pilot underlines the importance of building trust through holistic approaches to working with hard-to-reach populations through the creative arts.

Corrigendum: Disseminated tuberculosis and diagnosis delay during the COVID-19 era in a Western European country: a case series analysis

[This corrects the article DOI: 10.3389/fpubh.2023.1175482.].

The Use of Adaptive Sampling to Reach Disadvantaged Populations for Immunization Programs and Assessments: A Systematic Review

Vaccines prevent 4-5 million deaths every year, but inequities in vaccine coverage persist among key disadvantaged subpopulations. Under-immunized subpopulations (e.g., migrants, slum residents) may be consistently missed with conventional methods for estimating immunization coverage and assessing vaccination barriers. Adaptive sampling, such as respondent-driven sampling, may offer useful strategies for identifying and collecting data from these subpopulations that are often "hidden" or hard-to-reach. However, use of these adaptive sampling approaches in the field of global immunization has not been systematically documented. We searched PubMed, Scopus, and Embase databases to identify eligible studies published through November 2020 that used an adaptive sampling method to collect immunization-related data. From the eligible studies, we extracted relevant data on their objectives, setting and target population, and sampling methods. We categorized sampling methods and assessed their frequencies. Twenty-three studies met the inclusion criteria out of the 3069 articles screened for eligibility. Peer-driven sampling was the most frequently used adaptive sampling method (57%), followed by geospatial sampling (30%), venue-based sampling (17%), ethnographic mapping (9%), and compact segment sampling (9%). Sixty-one percent of studies were conducted in upper-middle-income or high-income countries. Data on immunization uptake were collected in 65% of studies, and data on knowledge and attitudes about immunizations were collected in 57% of studies. We found limited use of adaptive sampling methods in measuring immunization coverage and understanding determinants of vaccination uptake. The current under-utilization of adaptive sampling approaches leaves much room for improvement in how immunization programs calibrate their strategies to reach "hidden" subpopulations.

Innovating a Community-driven Enumeration and Needs Assessment of People Experiencing Homelessness: A Network Sampling Approach for the HUD-Mandated Point-in-Time Count

To enumerate people experiencing homelessness in the U.S., the federal Department of Housing and Urban Development (HUD) mandates its designated local jurisdictions regularly conduct a crude census of this population. This Point-in-Time (PIT) body count, typically conducted on a January night by volunteers with flashlights and clipboards, is often followed by interviews with a separate convenience sample. Here, we propose employing a network-based (peer-referral) respondent-driven sampling (RDS) method to generate a representative sample of unsheltered people, accompanied by a novel method to generate a statistical estimate of the number of unsheltered people in the jurisdiction. First, we develop a power analysis for the sample size of our RDS survey to count unsheltered people experiencing homelessness. Then, we conducted three large-scale population-representative samples in King County, WA (Seattle metro) in 2022, 2023, and 2024. We describe the data collection and the application of our new method, comparing the 2020 PIT count (the last visual PIT count performed in King County) to the new method 2022 and 2024 PIT counts. We conclude with a discussion and future directions.

The Healthy and Active Fund: Lessons From the Evaluation Experiences of Community-Based Physical Activity Projects in Wales

BACKGROUND

The "Healthy and Active Fund" involved 17 community-based projects focused on the delivery of physical activity interventions, led by a variety of public and third sector organizations. As a novel, direct approach to capturing impact at this level, these organizations were encouraged to robustly evaluate and monitor their own project's outcomes, with core funds allocated to this process. This study aimed to explore project experiences of planning and completing evaluation activities, to better understand how to support community-based practice improvement.

METHODS

In-depth semistructured interviews were completed with individuals who had supported their project's evaluation. Reflexive thematic analysis was used to identify key facilitators and barriers associated with evaluation in this context.

RESULTS

Across 3 identified themes, participants (N = 15, 12 projects) referred to a need for greater organizational capacity and expertise, familiarity with evaluation methods, partnership-working, inclusivity, and flexibility, particularly when collecting data from project beneficiaries. Overarching program support (eg, case officers) was viewed as a valuable resource that was disrupted by COVID-19. Participants highlighted the resilience of their projects when engaging with evaluation processes and acknowledged wider learning across organization networks as a result of this success.

CONCLUSIONS

This study shows that projects may benefit from closer support and external expertise for research and evaluation. There is willingness by third sector and public bodies to adopt research and evaluation methods into routine practice, but significant barriers persist. Future programs should continue to support adaptable approaches to evaluation at community-level, to better progress health and well-being goals for diverse populations.