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Perceived Stress Scale-10:
Scoring and Interpretation
The Perceived Stress Scale-10 (PSS-10) is a ten-item self-report measure of how unpredictable, uncontrollable and overloaded a person judges life to have been over the past month, scored from 0 to 40 (Cohen & Williamson, 1988). Four reversals shape PSS-10 scoring, and the total carries no clinical cut-off; the page adds SPSS and R syntax, the published reliability and factor-structure findings, and a sentence stating how the total was scored.
What the PSS-10 Measures
The PSS-10 captures perceived stress: how far a person appraises the situations of the previous month as unpredictable, uncontrollable or overloading. The original scale had 14 items (Cohen, Kamarck & Mermelstein, 1983), and Cohen and Williamson (1988) examined the shortened 10-item form in a probability sample of US adults.
Because it asks about appraisal instead of counting stressful life events, the scale turns up in health psychology, occupational health and public health research, often as an exposure, a mediator or an outcome. It does not diagnose a psychiatric disorder. Scores are best read against the distribution in your own study or against defensible population norms.
Structure of the PSS-10
- Items: ten questions about feelings and thoughts during the past month.
- Response scale: five levels coded 0 to 4, from never to very often.
- Reverse-scored items: 4, 5, 7 and 8, the four positively worded items.
- Subscales: none in conventional reporting. Some factor analyses separate positively and negatively worded items, but those groupings do not replace the standard total.
- Total: one summed score from 0 to 40.
- Other versions: the 14-item PSS and the four-item PSS-4 exist and are not numerically equivalent to the PSS-10.
The instrument itself is available from the Cohen Laboratory, Carnegie Mellon University.
How to Score the PSS-10
- Check that pss1 to pss10 hold the original five response levels, coded as integers from 0 to 4.
- Reverse items 4, 5, 7 and 8 as 4 minus the response, so 0 becomes 4, 1 becomes 3 and 2 stays 2.
- Add the six unchanged and the four reversed items to obtain pss10_total, which ranges from 0 to 40.
- Decide on a missing-item rule. The cited PSS-10 sources set no universal prorating rule, so the code below requires all ten items. If your protocol allows another rule, state it in the methods section.
* Illustrative syntax: variables must already be valid item scores (0 to 4).
COMPUTE pss4_r = 4 - pss4.
COMPUTE pss5_r = 4 - pss5.
COMPUTE pss7_r = 4 - pss7.
COMPUTE pss8_r = 4 - pss8.
COMPUTE pss10_total = SUM.10(pss1, pss2, pss3, pss4_r, pss5_r, pss6, pss7_r, pss8_r, pss9, pss10).
EXECUTE.# data: one row per respondent; items pss1 to pss10 coded 0 to 4.
data$pss4_r <- 4 - data$pss4
data$pss5_r <- 4 - data$pss5
data$pss7_r <- 4 - data$pss7
data$pss8_r <- 4 - data$pss8
data$pss10_total <- rowSums(data[c("pss1", "pss2", "pss3", "pss4_r", "pss5_r", "pss6", "pss7_r", "pss8_r", "pss9", "pss10")], na.rm = FALSE)Interpreting PSS-10 Scores
| Score band | Interpretation |
|---|---|
| 0 to 40 | Continuous perceived-stress total; higher = more perceived stress |
| Clinical cut-off | None established by the scale developer |
Source: Cohen Laboratory, Carnegie Mellon University; CORC PSS-10 instrument guidance.
In Perceived Stress Scale scoring, a higher total reflects a stronger tendency to appraise the past month as stressful. The developer defines no low, moderate or high categories, so labels circulating online should not be presented as validated. If you need groups, use population norms or a transparent, study-specific split, and show the continuous distribution beside it.
Complete the four reversals before summing, because a total that skips them runs in the wrong direction for those items. Factor-analytic work has also questioned strict unidimensionality in some populations, so inspect the item structure when your research question depends on it.
Psychometric Properties
| Property | Published finding | Source |
|---|---|---|
| Internal consistency | α = .78 for the 10-item form in the US probability sample | Cohen & Williamson (1988) |
| Test-retest | One-week r = .85 and two-week r = .82 in the PCS1 sample (n = 274); α = .86 in a combined sample (n = 1,142) | Carnegie Mellon University (n.d.), Common Cold Project |
| Construct validity | Associations with perceived control, psychological distress and related outcomes; later reviews support generally acceptable validity | Cohen et al. (1983); Lee (2012) |
| Factor structure | A large population-based study found that a two-dimensional representation fit better than strict unidimensionality | Nielsen et al. (2016) |
| Screening accuracy | No diagnostic threshold, sensitivity or specificity is defined for the total score | Cohen Laboratory; CORC |
These are source-specific results and cannot be assumed to hold as reliability or accuracy estimates in a new sample.
Using the PSS-10 in a Study
Analyze the total as a continuous variable and summarize it with a mean and standard deviation, or a median and quartiles when the distribution is skewed, without turning a score of 20 into a clinical statement. Perceived stress is often placed between an exposure and a health outcome, as in a Mediation Analysis; with observational data, describe the paths as associations unless the design supports a causal reading. When stress enters a model alongside demographic and clinical covariates, Hierarchical Regression lets you report what the stress block adds, with confidence intervals.
Compute alpha from your own data with Reliability Analysis (Cronbach’s Alpha), and check the score distribution separately for ceiling and floor effects. If a two-factor wording model matters for your hypothesis, examine it explicitly, for example through Exploratory Factor Analysis (EFA), rather than relying on alpha alone. The sample size you need follows from the intended model and the precision required, not from the ten items.
Related field: Health Psychology
Reporting the PSS-10
Perceived stress was measured with the 10-item Perceived Stress Scale (PSS-10; Cohen & Williamson, 1988). Responses were coded from 0 to 4, and items 4, 5, 7 and 8 were reverse coded before summation. Total scores ranged from 0 to 40, with higher scores reflecting greater perceived stress. Cronbach’s alpha in the present sample was [α = XX].
References
Carnegie Mellon University. (n.d.). Perceived Stress: Common Cold Project. https://www.cmu.edu/common-cold-project/measures-by-study/psychological-and-social-constructs/stress-measures/perceived-stress.html
Carnegie Mellon University. (n.d.). PSS scoring. https://www.cmu.edu/dietrich/psychology/stress-immunity-disease-lab/scales/html/pssscoring.html
Cohen, S., Kamarck, T., & Mermelstein, R. (1983). A global measure of perceived stress. Journal of Health and Social Behavior, 24(4), 385-396. https://doi.org/10.2307/2136404
Cohen, S., & Williamson, G. M. (1988). Perceived stress in a probability sample of the United States. In S. Spacapan & S. Oskamp (Eds.), The social psychology of health: Claremont Symposium on applied social psychology (pp. 31-67). Sage.
Lee, E.-H. (2012). Review of the psychometric evidence of the perceived stress scale. Asian Nursing Research, 6(4), 121-127. https://doi.org/10.1016/j.anr.2012.08.004
Nielsen, M. G., Ørnbøl, E., Vestergaard, M., Bech, P., Larsen, F. B., Lasgaard, M., & Christensen, K. S. (2016). The construct validity of the Perceived Stress Scale. Journal of Psychosomatic Research, 84, 22-30. https://doi.org/10.1016/j.jpsychores.2016.03.009
Frequently Asked Questions
Which PSS-10 items are reverse scored?
Items 4, 5, 7 and 8, the four positively worded items. Each is scored as 4 minus the 0 to 4 response before the ten items are added.
Does the developer define low or high stress cut-offs?
No. The PSS-10 is a continuous measure of perceived stress without official diagnostic cut-offs, so any category you report should come from population norms or a stated, study-specific rule.
Can a PSS-10 score show that someone has chronic stress?
No. The total summarizes a respondent’s appraisals over the previous month. It is neither a psychiatric diagnosis nor a record of how long the stress has lasted.
Why might alpha differ from one PSS-10 study to the next?
Internal consistency depends on the sample and may reflect how positively and negatively worded items behave in that population. Report the coefficient from your own data rather than borrowing a published value.
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