Reliability and validity of 2 single-item measures of psychosocial stress.
BACKGROUND
Practical limitations in epidemiologic research may necessitate use of only a few questions for assessing the complex phenomenon called "stress." The objective of this study was to evaluate the measurement characteristics of 2 single-item measures on the amount of stress and the ability to handle stress.


METHODS
We selected 218 adults age 50 to 76 years living in western Washington state from a large prospective cohort study of lifestyle factors and cancer risk to evaluate the 3-month test-retest reliability and intermethod reliability of the stress questions. To assess the latter, we compared 2 single-item measures on stress with 3 more fully validated multi-item instruments on perceived stress, daily hassles, and life events, which assessed the same underlying constructs as the single-item measures.


RESULTS
The test-retest reliabilities for the single-item stress measures were good (kappa and intraclass correlations between 0.66 and 0.74). The intermethod reliabilities comparing the 2 single-item stress measures with 3 multi-item instruments were moderate (r = 0.31-0.46) and comparable to correlations observed among the 3 multi-item instruments (r = 0.25-0.47).


CONCLUSIONS
The 2 single-item stress measures are reliable at measuring stress with validity similar to longer questionnaires. Single-item measures offer a practical instrument for assessing stress in large prospective epidemiologic studies that lack space for longer instruments.
Littman
Alyson J
AJ
Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA. alittman@fhcrc.org
White
Emily
E
Satia
Jessie A
JA
Bowen
Deborah J
DJ
Kristal
Alan R
AR
D000368:Aged; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013315:Stress, Psychological / Q000175:diagnosis* / Q000523:psychology; D011795:Surveys and Questionnaires