To the Editor,
The COVID-19 Pandemic-Related Stress Scale (PSS-10-C) was presented amidst the worldwide coronavirus disease (COVID-19) outbreak.1 The PSS-10-C is an adaptation of the famous Scale of Perceived Stress (PSS-10).2 The instrument's relevance is evidenced by several citations of using the PSS-C-10 in the world context.3, 4, 5 The PSS-10-C presented a one-dimensional structure, without a confirmatory analysis factorial, and high internal consistency; however, the need to make adjustments in PSS-10-C was noted.1
Since perspective focused on the writing of the items, a review of the PSS-10-C suggested that the Spanish item 6 (’I have felt unable to face the things I have to do to control the possible infection’) could partly explain that the factorial solution was not wholly satisfactory in explaining less than 50% of the variance.6 Furthermore, item 6 was scored directly and was preceded and followed by two items scored inversely.1 Often, these details can have a significant impact on the performance of the measurement scales.7
A sample of 1136 students from all majors of a Colombian university participated. Participants include ages between 18 and 29 years (mean, 22 ± 3], currently called emerging adults.8 66% of the sample was female, and 79% of residents in low-income areas were included. Students completed online an adjusted version of the PSS-10-C that only has a modification (in italics) in Spanish item 6 to which the wording was adjusted (’I have felt able to face the things that I have to do to control a possible infection’), and the meaning of the qualification was changed from direct to reverse. Items 1, 2, 3, 9, and 10 were scored directly from 0 to 4, and items 4, 5, 6, 7, and 8 were reversed from 4 to 0.1 Exploratory factor analysis (EFA) and confirmatory (EFA) were performed (CFA). Besides, Cronbach's alpha was calculated as an indicator of internal consistency.9 The analysis was performed using IBM-SPSS version 23.10 This study was approved by an institutional research ethics committee (Act 002 of an ordinary meeting, March 26th, 2020).
In the EFA, the coefficient was KMO = .86, and Bartlett's test showed χ2 = 3.985.3, df = 54 and P < .001. Two factors were retained, factor 1 (’distress’) (items 1, 2, 3, 9, and 10), which showed an Eigenvalue of 4.24 that explained 42.4% of the variance and factor 2 (’coping’) (items 4, 5, 6, 7 and 8) that presented Eigenvalue of 1.42 responsible for 14.2% of the variance. The correlation between the factors was .55. The CFA showed the goodness-of-fit indexes the two-dimensional model of the PSS-10-C (χ2 = 295.6; df = 34; P < .001; χ2/df = 8.7; RMSEA = .08; 90%CI, 0.07-0.09; CFI = .93; TLI = .91; SRMR = .05). The global PSS-10-C showed Cronbach's α=.85, factor 1 = .83, and factor 2 = .77.
A slight modification in the writing and way of rating an item can produce a significant change in an instrument's psychometric performance, such as disqualifying adjectives, negative sentences, or other strategies that can change the rating sense of items.7 The two-dimensional solution for the PSS-10-C is not novel; it has been previously reported for the PSS-10.11, 12, 13 The 2 factors retained more than 50% of the variance, as is usually recommended,6 and indicators of goodness-of-fit are good.14, 15 Also, this version of the PSS-C-10, with the adjustment of item 6, showed high internal consistency (.85), as the previous version (.86).1
In conclusion, the PSS-10-C is a valid and reliable tool among emerging adult students from a Colombian university. These indicators need to be corroborated in future research.
Funding
The Universidad del Magdalena supported Adalberto Campo-Arias and John Carlos Pedrozo-Pupo, and the Instituto de Investigación del Comportamiento Humanao supported Edwin Herazo.
References
- 1.Campo-Arias A., Pedrozo-Cortés M.J., Pedrozo-Pupo J.C. Pandemic-Related Perceived Stress Scale of COVID-19: An exploration of online psychometric performance. Rev Colomb Psiquiatr. 2020;49:229–230. doi: 10.1016/j.rcp.2020.05.005. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Cohen S., Kamarck T., Mermelstein R. A global measure of perceived stress. J Health Soc Behav. 1983;24:385–396. [PubMed] [Google Scholar]
- 3.Campo-Arias A., Perdomo-Rojas J.A., Caballero-Domínguez C.C. Social capital and perceived stress related to coronavirus disease in Colombia. J Epidemiol Community Health. 2020;74:872. doi: 10.1136/jech-2020-215005. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Hernandez-Garcia F., Gongora-Gomez O., Gonzalez-Velazquez V.E., Pedraza-Rodriguez E.M., Zamora-Fung R., Lazo L.A. Stress perceived by students of the medical sciences in Cuba toward the COVID-19 pandemic: results of an online survey. medRxiv. 2020 doi: 10.1101/2020.12.16.20248345. [DOI] [PubMed] [Google Scholar]
- 5.Bermejo-Martins E., Luis E.O., Sarrionandia A. Different responses to stress, health practices and self-care during COVID-19 lockdown: A stratified analysis. Preprints. 2021 doi: 10.20944/preprints202102.0092.v1. 2021020092. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Campo-Arias A., Herazo E., Oviedo H.C. Factor analysis: Principles to evaluate measurement tools for mental health. Rev Colomb Psiquiatr. 2012;41:659–671. doi: 10.1016/S0034-7450(14)60036-6. [DOI] [PubMed] [Google Scholar]
- 7.Liu M., Keusch F. Effects of scale direction on response style of ordinal rating scales. J Offic Stat. 2017;33:137–154. [Google Scholar]
- 8.Arnett J.J. Emerging adulthood: A theory of development from the late teens through the twenties. Am Psychol. 2000;55:469–489. [PubMed] [Google Scholar]
- 9.Cronbach J. Coefficient alpha and the internal structure of tests. Psychometrika. 1951;16:297–334. [Google Scholar]
- 10.IBM-SPSS Statistics for Windows, version 23.0. Armonk: SPSS. Inc.; 2015.
- 11.Wang Z., Chen J., Boyd J.E. Psychometric properties of the Chinese version of the Perceived Stress Scale in policewomen. PloS One. 2011;6:e28610. doi: 10.1371/journal.pone.0028610. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Ng S.M. Validation of the 10-item Chinese perceived stress scale in elderly service workers: one-factor versus two-factor structure. BMC Psychol. 2013;1:9. doi: 10.1186/2050-7283-1-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Sandhu S.S., Ismail N.H., Rampal K.G. The Malay version of the perceived stress scale (PSS)-10 is a reliable and valid measure for stress among nurses in Malaysia. Malay J Med Sci. 2015;22:26–31. [PMC free article] [PubMed] [Google Scholar]
- 14.Hu L.T., Bentler P.M. Cutoff criteria for fit indexes in covariance structure analysis: Conventional criteria versus new alternatives. Struct Equat Model. 1999;6:1–55. [Google Scholar]
- 15.Wheaton B., Muthen B., Alwin D.F., Summers G.F. In: Sociological methodology. Heise D.E., editor. Jossey-Bass; San Francisco: 1977. Assessing reliability and stability in panel models; pp. 84–136. [Google Scholar]