Reliability and Validity of Single-Item Self-Reports: With Special Relevance to College Students' Alcohol Use, Religiosity, Study, and Social Life

The authors tested the assumption that single-item measures have unacceptably low reliability and validity. On 2 occasions 11 weeks apart, college students reported on the frequency and quantity of alcohol consumption, 2 religious behaviors, time of study and of socializing (focal items), and other qualities and characteristics. Most test-retest reliabilities were good to excellent; objective facts were more reliable than subjective evaluations; and target items had good validity when correlated with 2-week nightly log records of corresponding behaviors in a multimethod multitrait matrix. The exception was self-reported Study, with relatively low reliability and validity, suggesting the non-trait-like quality of this behavior. Single-item measures may be better than commonly thought.