A psychometric evaluation of the Swedish translation of the Perceived Stress Scale: a Rasch analysis

BACKGROUND

Stress reflects physical and psychological reactions to imposing demands and is often measured using self-reports. A widely-used instrument is the Perceived Stress Scale (PSS), intended to capture more general aspects of stress. A Swedish translation of the PSS is available but has not previously been examined using modern test theory approaches. The aim of the current study is to apply Rasch analysis to further the understanding of the PSS' measurement properties, and, in turn, improve its utility in different settings.

METHODS

Data from 793 university students was used to investigate the dimensionality of different version of the PSS (14, 10, and 4 items) as well as potential response patterns among the participants.

RESULTS

The current study demonstrates that the PSS-14 has two separate factors, divided between negatively worded items (perceived stress) and positively worded items (perceived [lack of] control), although with only the negative subscale exhibiting good reliability. Response patterns were analyzed using Differential Item Functioning, which did not find an influence of gender on any of the items, but for age regarding the positive subscale (items 6 and 9). The PSS-10 also demonstrated adequate reliability for the negative subscale, but the PSS-4 was not deemed suitable as a unidimensional scale.

CONCLUSIONS

Based on the results, none of the versions of the PSS should be used by sum-scoring all of the items. Only the negative items from the PSS-14 or PSS-10 can be used as unidimensional scales to measure general aspects of stress. As for different response patterns, gender may nevertheless be important to consider, as prior research has found differences on several items. Meanwhile, content validity is discussed, questioning the relevance of anger and being upset when measuring more general aspects of stress. Finally, a table to convert the PSS-7 (i.e., negative items) ordinal sum scores to interval level scores is provided.

Implementing a Standardized Effect Size in the POLYSIBTEST Procedure

A study was conducted to implement the use of a standardized effect size and corresponding classification guidelines for polytomous data with the POLYSIBTEST procedure and compare those guidelines with prior recommendations. Two simulation studies were included. The first identifies new unstandardized test heuristics for classifying moderate and large differential item functioning (DIF) for polytomous response data with three to seven response options. These are provided for researchers studying polytomous data using POLYSIBTEST software that has been published previously. The second simulation study provides one pair of standardized effect size heuristics that can be employed with items having any number of response options and compares true-positive and false-positive rates for the standardized effect size proposed by Weese with one proposed by Zwick et al. and two unstandardized classification procedures (Gierl; Golia). All four procedures retained false-positive rates generally below the level of significance at both moderate and large DIF levels. However, Weese's standardized effect size was not affected by sample size and provided slightly higher true-positive rates than the Zwick et al. and Golia's recommendations, while flagging substantially fewer items that might be characterized as having negligible DIF when compared with Gierl's suggested criterion. The proposed effect size allows for easier use and interpretation by practitioners as it can be applied to items with any number of response options and is interpreted as a difference in standard deviation units.

Perceived Stress and Perceived Lack of Control of Spanish Education-Degree University Students: Differences Dependent on Degree Year, Basis for Admission and Gender

Stress in higher education students is an issue of growing concern, as stress impacts quality of life and has been linked to drop-out from higher education. The aim was to investigate how stress was related to how far along students were in their degree program, using the Spanish Perceived Stress Scale (PSS10). We expected 1) first-year education students to experience more perceived lack of control than second-year students, 2) second-year students to experience more perceived stress than first-year students. Participants were students in three university education-degree programs (N = 399). The psychometric properties of the Perceived Stress (PS) and Perceived Lack of Control (PLC) subscales were investigated using Rasch models. One item was eliminated from each subscale. The estimated interval-level Rasch scores were utilized for testing hypotheses with general linear models. Results showed a somewhat more complex pattern than predicted as interaction effects between degree year and gender and between degree year and basis for admission were found.

Assessing the validity, reliability and efficacy of the Cross-Cultural Stress Scale (CCSS) for psychosomatic studies

OBJECTIVE

The impact of stressful life events (SLEs) on health has been empirically studied with significant correlations documented. We developed a comprehensive stress rating toolkit, the Cross-Cultural Stress Scale (CCSS) from a triangulated qualitative research study. This article describes our pilot test of the scale to explore demographic-specific patterns of SLE scores and evaluate the scale's aptitude in assessing the stress-health correlation.

METHODS

The face and content-validated CCSS was shared via a web-based survey to diverse individuals grouped by: (a) gender, (b) age, (c) race and ethnicity, (d) native, foreign-born or first-generation, (e) educational attainment, and (f) income. Participants from the Amazon crowdsourcing marketplace MTurk (N = 216) first indicated perceived stress intensities assuming experiences of all the SLEs in the CCSS. They then selected SLEs they had personally experienced in the last 12 months (N = 176). Multivariable analyses were conducted on perceived intensities. Correlations of experienced SLEs with self-reported health based on the Centers for Disease Control and Prevention (CDC) Health Related Quality of Life (HRQOL) indicators measured by the Behavioral Risk Factors Surveillance System (BRFSS) were analyzed.

RESULTS

We validated the CCSS and obtained a high internal reliability (Cronbach's alpha >0.9). We found significant differences in stress rating by and within demographics. We also correlated stress to perceived health using the HRQOL and presence of a chronic disease ascertaining the stress-health hypothesis.

LIMITATION

Sampling limitations observed include data drawn from a convenience sample.

CONCLUSION

Despite sampling limitations, our research highlights demographic-specific stressors and offers an updated methodology in the stress-health correlation.

An Exploration of Stress: Leveraging Online Data from Crowdsourcing Platforms

Background: Early detection of community health risk factors such as stress is of great interest to health policymakers, but representative data collection is often expensive and time-consuming. It is important to investigate the use of alternative means of data collection such as crowdsourcing platforms.

Methods: An online sample of Amazon Mechanical Turk (MTurk) workers (N = 500) filled out, for themselves and their child, demographic information and the 10-item Perceived Stress Scale (PSS-10), designed to measure the degree to which situations in one’s life are appraised as stressful. Internal consistency reliability of the PSS-10 was examined via Cronbach’s alpha. Analysis of variance (ANOVA) was utilized to explore trends in the average perceived stress of both adults and their children. Last, Rasch trees were utilized to detect differential item functioning (DIF) in the set of PSS-10 items.

Results: The PSS-10 showed adequate internal consistency reliability (Cronbach’s alpha = 0.73). ANOVA results suggested that stress scores significantly differed by education (p = 0.024), employment status (p = 0.0004), and social media usage (p = 0.015). Rasch trees, a recursive partitioning technique based on the Rasch model, indicated that items on the PSS-10 displayed DIF attributable to physical health for adults and social media usage for children.

Conclusion: The key conclusion is that this data collection scheme shows promise, allowing public health officials to examine health risk factors such as perceived stress quickly and cost effectively.

The Factorial Validity of the Norwegian Version of the Multicomponent Training Distress Scale (MTDS-N)

BACKGROUND

Athlete self-report measures (ASRM) are methods of athlete monitoring, which have gained considerable popularity in recent years. The Multicomponent Training Distress Scale (MTDS), consisting of 22 items, is a promising self-report measure to assess training distress among athletes. The present study aimed to investigate the factorial validity of the Norwegian version of MTDS (MTDS-N) among student-athletes (n = 632) attending the optional program subject "Top-Level Sports" in upper secondary schools in Norway.

METHODS

A confirmatory factor analysis (CFA) was conducted to assess the six-factor model proposed by Main and Grove (2009). McDonald's omega (ω) along with confidence intervals (CIs) were used to estimate scale reliability. After examining the fit of the CFA model in the total sample, covariates were included to investigate group differences in latent variables of MTDS-N, resulting in the multiple indicators multiple causes (MIMIC) model. Further, direct paths between the covariates and the factor indicators were included in an extended MIMIC model to investigate whether responses to items differed between groups, resulting in differential item functioning (DIF).

RESULTS

When modification indices (MIs) were taken into consideration, the alternative CFA model revealed that MTDS-N is an acceptable psychometric tool with a good fit index. The factors in MTDS-N all constituted high scale reliability with McDonald's ω ranging from 0.725-0.862. The results indicated statistically significant group differences in factor scores for gender, type of sport, hours of training per week, school program, and school level. Further, results showed that DIF occurred in 13 of the MTDS-N items. The student-athletes' reports of training distress were moderate.

CONCLUSION

The MTDS-N may be suitable for use in a Norwegian population to assess student-athletes' training distress in a reliable manner. The indications of group effects suggest that caution should be used if one is interested in making group comparisons when the MTDS-N is used among student-athletes in Norway until further research is conducted.

Relationship Between Gender, Stress, and Quality of Social Support

BACKGROUND

Research suggests that gender differences exist in both stress and how social support is utilized and that the relationship between stress and social support may not be linear.

METHODS

An internet survey of n = 1080 participants was conducted evaluating quality and quantity of social support, gender, age, and perceived stress and coping.

RESULTS

Reported quality of social support, gender, and age significantly predicted perceived stress and that there was a curvilinear interaction between the quality of social support and gender which significantly predicted perceived stress.

CONCLUSION

The current findings supported Taylor's Tend and Befriend theory that females have higher reported stress levels, a larger support network, and report more quality in their social support.Practitioner points:  • Males and females may manifest stress differently in their relationships. • When working with males and females in practice it may be important to understand the depth and breadth of their social networks and how they utilize those networks. • Females indicate higher levels of stress and greater social support quality. • It is important to understand that one's social network can be an important source of support (a coping mechanism) but that it can also serve as a stressor in some cases.

Measuring stress in Australia: validation of the perceived stress scale (PSS-14) in a national sample

Background

In Australia, the stress levels have increased over the years, impacting on the physical and mental health of the general population. The aim of the present study was to evaluate the validity and reliability of the PSS-14 in an Australian population.

Methods

The PSS-14 was applied to a large national sample comprising 3857 Australians in the population-based cross-sectional study Australia’s National Survey of Adult Oral Health 2004–2006. The psychometric properties analyzed with the Rasch model and Graphical Log-linear Rasch models were: model fit, item fit, local dependence, differential item functioning, unidimensionality, reliability, targeting and criterion validity.

Results

The PSS-14 did not fit the pure RM (χ2 (55) = 3828.3, p = < 0.001) and the unidimensionality of the whole scale was rejected (p = < 0.001). The Perceived Stress (χ2 (27) = 1409.7, p = < 0.001) and Perceived Control (χ2 (27) = 713.4, p = < 0.001) subscales did not fit the pure RM. After the deletion of two items, the Perceived Stress subscale (χ2 (96) = 94.4, p = 0.440) fitted a GLLRM, while the Perceived Control scale (χ2 (55) = 62.50, p = 0.224) fitted a GLLRM after the exclusion of four misfitting items.

Conclusions

The Perceived Stress subscale displayed adequate psychometric properties after the deletion of two items; however, the majority of problems centered around the Perceived Control subscale. The presence of differential item functioning among four items indicates that adjustment of total scores is required to avoid measurement bias. Recommendations for future applications in Australia are provided.

Factor Structure of the 10-Item Perceived Stress Scale and Measurement Invariance Across Genders Among Chinese Adolescents

BACKGROUND

Chinese adolescents encounter a lot of stressors, such as academic burden and parental pressure. However, little is known about their perception of stress. The 10-item Perceived Stress Scale (PSS-10) is a widely used instrument to measure individuals' appraisal of global stress in academic research and clinical practice. The current study aimed to evaluate the best-fit factor structure model of the PSS-10 and the measurement invariance across genders in Chinese adolescents.

METHODS

A total of 1,574 Chinese senior high school students completed the PSS-10 (mean age = 15.26 ± 0.56 years, female = 54%). Confirmatory factor analysis (CFA) was conducted to determine the factor structure of the PSS-10. Multigroup CFA was carried out to test the measurement invariance of the PSS-10 across genders. A subsample (N = 1,060) answered additional questionnaires measuring stressful life events, anxiety, and depression to examine the convergent and concurrent validity of the PSS-10.

RESULTS

The two-factor model was supported [i.e., χ2 (34) = 332.224, p < 0.001; non-normal fit index (NNFI) = 0.901, comparative fit index (CFI) = 0.925, root mean square error of approximation (RMSEA) = 0.075, standardized root mean square residual (SRMR) = 0.051]. Importantly, the model exhibited strong measurement invariance across female and male groups. Furthermore, the PSS-10 had adequate convergent validity for stressful life events (number: r = 0.13, p < 0.001; impact: r = 0.23, p < 0.001) and could explain incremental variance in predicting anxiety (ΔR 2 = 0.13, β = 0.38, p < 0.001) and depression (ΔR 2 = 0.16, β = 0.41, p < 0.001), suggesting excellent concurrent validity.

CONCLUSION

A two-factor model best fits the structure of PSS-10 among Chinese adolescents, with strong measurement invariance between gender groups, demonstrating its validity for assessing perceived stress among Chinese adolescents.

Stress beyond coping? A Rasch analysis of the Perceived Stress Scale (PSS-14) in an Aboriginal population

The history of colonization contributed to Aboriginal and Torres Strait Islanders becoming one of the most disadvantaged groups in Australia. The multiple social inequalities, and therefore the constant insecurities for many about low income, poor living conditions, unemployment, and discrimination, generate chronic stress in this population. In the Baby Teeth Talk Study, an oral-health randomized controlled trial, the Perceived Stress Scale (PSS-14) was administered to 367 pregnant Aboriginal women at baseline. The aim of the present study was to evaluate the validity and reliability of the PSS-14 in an Aboriginal population. The study analysed: (a) model fit; (b) dimensionality; (c) local dependence; (d) differential item functioning; (e) threshold ordering and item fit; (f) targeting; (g) reliability; and (h) criterion validity. The dimensionality analysis indicated a two-factor structure, with negatively and positively worded items clustering together and 21.7% (95% Agresti-Coull C.I. [17.8%, 26.2%]) statistically significant t-tests between the persons' estimates. After the creation of composite items, the revised Perceived Distress (χ2 (21) = 11.74, p = 0.946) and Perceived Coping (χ2 (28) = 17.63, p = 0.935) subscales fitted the Rasch model. Reliability was modest (PersonSeparationIndexdistress = 0.72; PersonSeparationIndexcoping = 0.76). The latent correlation between the Perceived Distress and Perceived Coping subscales was r = 0.14. It is hypothesized that the social inequalities experienced by the Aboriginal population are so pronounced that even Aboriginal pregnant women that perceived themselves as coping well with life challenges ended up endorsing items regarding high levels of stress. The present research showed that a revised PSS-14 is a culturally valid and modestly reliable psychological instrument to measure stress in a population of pregnant Aboriginal women in Australia.

Perceived cognitive deficits and depressive symptoms in patients with multiple sclerosis: Perceived stress and sleep quality as mediators

Multiple Sclerosis (MS), an autoimmune disorder marked by inflammation of the central nervous system, is associated with a myriad of symptoms. Individuals with MS are more likely to experience depressive symptoms, perhaps due to perceived cognitive impairments. Thus, we aimed to explore perceived stress and sleep deficits as potential mediators of the association between perceived cognitive deficits and depressive symptoms. We recruited a sample of 77 MS participants from an outpatient, university-based MS clinic in the United States. Participants ranged in age between 30 and 75 years old (M = 51.12; SD = 9.6), with more females than males (83% female; n = 64). Participants completed the Perceived Deficits Questionnaire, the Pittsburgh Sleep Quality Index, the Perceived Stress Scale, and the Center for Epidemiological Studies Depression Scale - Revised. Correlation analyses and mediation analyses were conducted with bootstrapping technique. Statistical analyses revealed that higher levels of perceived cognitive deficits were associated with lower quality of sleep, more perceived stress, and higher levels of depressive symptoms. Additionally, both perceived stress and sleep quality served as a significant mediator in the perceived cognitive impairments and depressive symptoms linkage. Our novel findings demonstrate the importance of underlying mechanisms (e.g., sleep quality and perceived stress) in the conceptualization of MS. Perceived stress and sleep quality are potentially modifiable factors, perhaps serving as a target for future treatment, to buffer risk of MS patients developing depression.

The German Version of the Perceived Stress Scale (PSS-10): Evaluation of Dimensionality, Validity, and Measurement Invariance With Exploratory and Confirmatory Bifactor Modeling

The Perceived Stress Scale (PSS) is a popular instrument for measuring the degree to which individuals appraise situations in their lives as excessively uncontrollable and overloaded. Despite its widespread use (e.g., for evaluating intervention effects in stress management studies), there is still no agreement on its factor structure. Hence, the aim of the present study was to examine the dimensionality, measurement invariance (i.e., across gender, samples, and time), reliability, and validity of the PSS. Data from 11,939 German adults (73% women) were used to establish an exploratory bifactor model for the PSS with one general and two specific factors and to cross-validate this model in a confirmatory bifactor model. The model displayed strong measurement invariance across gender and was replicated in Study 2 in data derived from six randomized controlled trials investigating a web-based stress management training. In Study 2 (overall N = 1,862), we found strong temporal invariance. Also, our analyses of concurrent and predictive validity showed associations with depressive symptoms, anxiety, and insomnia severity for the three latent PSS factors. These results show the implications of the bifactor structure of the PSS that might be of consequence in empirical research.

A Brief Stress Diagnostic Tool: The Short Stress Overload Scale

The Stress Overload Scale (SOS) has demonstrated validity in predicting pathological stress reactions; however, at 30 items, it is lengthy for some clinical applications. Here, two studies tested a 10-item SOS-Short (SOS-S). First, the SOS-S was compared with the SOS in a longitudinal community study ( n = 391), using indices of pathology as criterion measures. Results showed the SOS-S to be equivalent to the SOS in reliability and concurrent and predictive validity, although not quite as sensitive to somatic symptoms. Second, the SOS-S was compared to the 10-item Perceived Stress Scale in a cross-sectional community study ( n = 249), in which symptoms and response biases were also assessed. Results showed both measures to be susceptible to biasing, and the SOS-S to demonstrate superior validity when biases were controlled. The SOS-S appears a viable alternative to the SOS and the 10-item Perceived Stress Scale for assessing stress, and risk for sequelae, across a broad demographic spectrum.

The construct validity of the Perceived Stress Scale

OBJECTIVE

Stress impacts the quality of life and is associated with increased risk of mental and physical disorders. The Perceived Stress Scale (PSS) is widely used for measuring psychological distress. Although the instrument was originally defined as a single construct, several studies based on classical test theory suggest that a two-dimensional structure is more dominant. We aimed to explore the construct validity and dimensionality of the PSS-10 using modern test theory to determine if the scale is predominantly for a one- or a two-dimensional model.

METHODS

The study population consisted of 32,374 citizens who completed the PSS-10 as part of the Danish National Health Survey in 2010. We investigated the construct validity of the PSS-10 by CFA. We examined the scalability by investigating the fit of the data distribution in a unidimensional Rasch model and performing modification of response categories, persons and items. The scale dimensionality was additionally assessed by Mokken and Rasch analysis.

RESULTS

The PSS-10 did not fit the Rasch model. Item four indicated the largest misfit, and items four and seven displayed disordered thresholds. Unidimensionality could not be established although the data showed improved fit to the Rasch model for the two dimensions respectively with the positive and negative items. Mokken analysis revealed fit to the unidimensional model, but disordered thresholds were shown for item four.

CONCLUSION

Our large population-based study indicated scalability problems in the current version of the PSS-10. The conducted analysis overall revealed better statistical fit for a two-dimensional than a unidimensional model.

Confirmatory Factor Analysis of the Perceived Stress Scale-4 in a Community Sample

Although the Perceived Stress Scale (PSS) is among the most widely used measures of perceived stress, it has only recently begun to be tested in independent psychometric validation studies, and the four-item version of the PSS (PSS-4) (the briefest version of this measure) has never undergone testing to examine and confirm the originally proposed structure. To address this paucity of research, the present study (a) tested the structure of the PSS-4 in the first confirmatory factor analysis of the instrument and (b) tested for item-level gender differences in the PSS that have been demonstrated in other versions of this scale. Results indicated that the PSS four-item measure does not fit its proposed model. Additionally, score differences were observed for one item across genders.

Review of the psychometric evidence of the perceived stress scale

PURPOSE

The purpose of this study was to review articles related to the psychometric properties of the Perceived Stress Scale (PSS).

METHODS

Systematic literature searches of computerized databases were performed to identify articles on psychometric evaluation of the PSS.

RESULTS

The search finally identified 19 articles. Internal consistency reliability, factorial validity, and hypothesis validity of the PSS were well reported. However, the test-retest reliability and criterion validity were relatively rarely evaluated. In general, the psychometric properties of the 10-item PSS were found to be superior to those of the 14-item PSS, while those of the 4-item scale fared the worst. The psychometric properties of the PSS have been evaluated empirically mostly using populations of college students or workers.

CONCLUSION

Overall, the PSS is an easy-to-use questionnaire with established acceptable psychometric properties. However, future studies should evaluate these psychometric properties in greater depth, and validate the scale using diverse populations.