Is it the perceived stress scale (PSS) Undimimensional and invariant? A Bifactor analysis in Mexican adults

Fourteen-item perceived stress scale assessment using item response theory among pregnant women

The current study aimed to assess the psychometric properties of the Spanish language version of the 14-item Perceived Stress Scale (PSS-S) in a population of pregnant women who speak Spanish in Peru using item response theory (IRT). Our study consisted of 5,435 pregnant women who participated in the Pregnancy Outcomes Maternal and Infant Study (PrOMIS) cohort in Peru. Exploratory and confirmatory factor analyses were conducted to determine dimensionality of the scale in this population, and item response theory was conducted to determine the applicability of the PSS. The PSS consisted of a 2-factor questionnaire measuring perceived stress and coping capacity accounting for 77% of variability. The IRT analysis showed differences in item difficulty and discrimination. Item difficulty represents the level of the latent construct where 50% of respondents endorse a particular response, and item discrimination determines the rate of change of the probability of endorsing an item for differing ability levels. For the first factor, perceived stress, item 12 was the least difficult and item 2 was the most difficult. For the second factor, coping capacity, item 9 was the least difficult and item 6 was the most difficult. The Spanish version of the 14-item PSS can be a useful assessment tool for perceived stress, but more IRT should be done to delve further into the psychometric properties of the questionnaire to inform clinicians and policy makers more appropriately.

Dimensionality assessment in the presence of wording effects: A network psychometric and factorial approach

This study proposes a procedure for substantive dimensionality estimation in the presence of wording effects, the inconsistent response to regular and reversed self-report items. The procedure developed consists of subtracting an approximate estimate of the wording effects variance from the sample correlation matrix and then estimating the substantive dimensionality on the residual correlation matrix. This is achieved by estimating a random intercept factor with unit loadings for all the regular and unrecoded reversed items. The accuracy of the procedure was evaluated through an extensive simulation study that manipulated nine relevant variables and employed the exploratory graph analysis (EGA) and parallel analysis (PA) retention methods. The results indicated that combining the proposed procedure with EGA or PA achieved high accuracy in estimating the substantive latent dimensionality, but that EGA was superior. Additionally, the present findings shed light on the complex ways that wording effects impact the dimensionality estimates when the response bias in the data is ignored. A tutorial on substantive dimensionality estimation with the R package EGAnet is offered, as well as practical guidelines for applied researchers.

A systematic review and meta-analytic confirmatory factor analysis of the perceived stress scale (PSS-10 and PSS-14)

Stress is defined as a person's interaction with their environment that is thought to threaten or affect an individual's potential, resources, and well-being. The most popular instrument to assess perceived stress is the Perceived Stress Scale (PSS). Therefore, making a systematic review of studies testing the internal structure of PSS and conducting a Meta-Analytic Confirmatory Factor Analysis (MACFA) on the database created with the information obtained from these studies are the aims of this research. A total of 76 samples from 57 unique studies were included in this database using various inclusion criteria (total N for PSS-14 = 28,632, for PSS-10 = 46,053). The correlated two-factor model for PSS was confirmed by MACFA performed on the pooled correlation matrix generated by the random effects meta-analysis. Findings of dimensionality analyses, factor loadings, omega values, and measurement invariance showed that the model that best explained the factor structure of PSS was the correlated two-factor model. The strict measurement invariance of the PSS was achieved across age and clinical status, and the internal consistency was high according to the omega values. Several recommendations moving forward are discussed.

The dimensionality of the Perceived Stress Scale: The presence of opposing items is a source of measurement error

INTRODUCTION

The Perceived Stress Scale (PSS) is a widely recognized patient-reported outcome measure designed to assess an individual's level of perceived stress. The PSS consists of ten items, with six items phrased negatively and four phrased positively. Most studies have found that the PSS consists of two dimensions, with negative and positive items forming separate dimensions. However, some studies suggest a one-dimensional construct.

OBJECTIVE

We aimed to investigate the dimensionality of the PSS and the impact of wording effects on the measurement properties of the scale.

METHODS

We tested a modified version of the PSS (mPSS), with negative wording of all items. In a Danish sample, respondents were randomized to answer the PSS or the mPSS. We used confirmative factor analysis and Rasch analysis to assess the validity and reliability of the two versions. The proportion of person misfit was also evaluated.

RESULTS

A total of 326 respondents completed the PSS, whereas 306 completed the mPSS. For the PSS, a two-factor model fitted the data best, and the first positively formulated item showed under-discrimination (Rasch model item fit rejected). The mPSS had higher measurement precision than the PSS, but evidence of local dependence was seen for both versions. Fewer respondents gave improbable responses to the mPSS compared to the PSS.

LIMITATIONS

Data comes from three different respondent samples.

CONCLUSION

The PSS was deemed essentially unidimensional, with the extra variance being attributed to the reversed items. To reduce response bias, clinicians and researchers may apply the mPSS.

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.

The Perceived Stress Scale 2&2: a two-factorial German short version of the Perceived Stress Scale

Background

Stress is among the leading causes for diseases. The assessment of subjectively perceived stress is essential for resilience research. While the Perceived Stress Scale (PSS) is a widely used questionnaire, a German short version of the scale is not yet available. In the current study, we developed such a short version using a machine learning approach for item reduction to facilitate the simultaneous optimization of multiple psychometric criteria.

Method

We recruited 1,437 participants from an online panel, who completed the German long version of the PSS along with measures of mental health and resilience. An ant-colony-optimization algorithm was used to select items, taking reliability, and construct validity into account. Findings on validity were visualized by psychological network models.

Results

We replicated a bifactor structure for the long version of the PSS and derived a two-factor German short version of the PSS with four items, the PSS-2&2. Its factors helplessness and self-efficacy showed differential associations with mental health indicators and resilience-related factors, with helplessness being mainly linked to mental distress.

Conclusion

The valid and economic short version of the PSS lends itself to be used in future resilience research. Our findings highlight the importance of the two-factor structure of the PSS short versions and challenge the validity of commonly used one-factor models. In cases where the general stress factor is of interest, researchers should use the longer versions of the PSS that allow for the interpretation of total scores, while the PSS-2&2 allows of an economic assessment of the PSS factors helplessness and self-efficacy.

Randomized controlled trial of the Marriage Checkup: Stress outcomes

Several couple interventions targeting relationship distress also show beneficial effects on individual mental health. Yet, strikingly few studies report effects on perceived stress. This study examined the effects of a brief couple intervention, the Marriage Checkup (MC), on perceived stress. We randomly assigned 231 couples to receive two MCs (Weeks 7 and 51) or to a waitlist control. Survey data were collected at seven time points over 2 years and analyzed using multilevel models. We found no significant between-group treatment effects on average stress at any time point. However, women, but not men, in the intervention group experienced decreased stress after the second MC (d = -0.23) and more women in the intervention group (26.5%) compared with the control group (14.9%) experienced reliable improvements in stress after the second MC. Overall, the MC did not result in main effects on stress but caused temporary reliable change in terms of stress relief for women.

Perceived stress during the prenatal period: assessing measurement invariance of the Perceived Stress Scale (PSS-10) across cultures and birth parity

Maternal prenatal stress places a substantial burden on mother's mental health. Expectant mothers in low- and middle-income countries (LMICs) have thus far received less attention than mothers in high-income settings. This is particularly problematic, as a range of triggers, such as exposure to traumatic events (e.g. natural disasters, previous pregnancy losses) and adverse life circumstances (e.g. poverty, community violence), put mothers at increased risk of experiencing prenatal stress. The ten-item Perceived Stress Scale (PSS-10) is a widely recognised index of subjective experience of stress that is increasingly used in LMICs. However, evidence for its measurement equivalence across settings is lacking. This study aims to assess measurement invariance of the PSS-10 across eight LMICs and across birth parity. This research was carried out as part of the Evidence for Better Lives Study (EBLS, vrc.crim.cam.ac.uk/vrcresearch/EBLS). The PSS-10 was administered to N = 1,208 expectant mothers from Ghana, Jamaica, Pakistan, the Philippines, Romania, South Africa, Sri Lanka and Vietnam during the third trimester of pregnancy. Confirmatory factor analysis suggested a good model fit of a two-factor model across all sites, with items on experiences of stress loading onto a negative factor and items on perceived coping onto a positive factor. Configural and metric, but not full or partial scalar invariance, were established across all sites. Configural, metric and full scalar invariance could be established across birth parity. On average, first-time mothers reported less stress than mothers who already had children. Our findings indicate that the PSS-10 holds utility in assessing stress across a broad range of culturally diverse settings; however, caution should be taken when comparing mean stress levels across sites.