In a double-blind, randomized trial of methotrexate vs placebo in rheumatoid arthritis, the effect of treatment on physical, social, and emotional function was measured in two different ways: the same, standard measurements in all patients, and individualized measurements selected by the patients at the start of the trial as representing the functions they most wanted to have improved by treatment. On the standard measurements, methotrexate-treated patients fared better than placebo-treated patients in their physical, social, and emotional function by 11%, 5%, and 6%, respectively, results that, although statistically significant, were small. However, methotrexate-treated patients were 29% better in the individualized measures, a result that was both highly statistically significant and greater than the differences in the standard measurements or in joint counts, grip strength, proximal interphalangeal joint circumference, morning stiffness, or walking time. Because the individualized measurements were as efficient as the best direct joint examination measures, yet reflected functional outcomes of greatest importance to individual patients, they constitute useful measures for such trials.