Are Single-Item Global Ratings Useful for Assessing Health Status?

The research performance of the single-item self-rating In general, would you say your health is: excellent, very good, good, fair, or poor? was evaluated relative to the SF-36 General Health Scale that contains this item, using data for a sample of psychiatric outpatients who had co-occurring chronic physical conditions (N = 177). The scale was more robust than the single-item in cross-sectional validity tests and for predicting 2-year outcomes, but the single-item had stronger discriminant validity as a measure of physical health, especially in post-baseline analyses. Single-item and scale were both sensitive enough to detect change in perceived health over 2 years and a conditional experimental effect on health self-perceptions in a randomized trial. These findings demonstrate that a global single-item can be as valid, reliable, and sensitive as a multi-item scale for longitudinal research purposes, even if the scale performs better in cross-sectional surveys or as a screening measure.