What does it Mean? Anchoring Psychosocial Quality of Life Score Changes with Reference to Concurrent Changes

As customarily presented, the results of quality of life (QOL) studies tend more to puz-zle than to enlighten their intended audience of physicians, policy makers, and the gen-eral public. They ask, quite legitimately, what a difference of three “points ” on the Rand Mental Health Index means. Or; a fortiori, a difference of 0.17 “standard deviat-ions ” or “responsiveness units. ” How large need a difference be in order to justifr action or decision: ‘ At the level of the individual question, the numbers have plain, intuitive content. But once they are combined into statistical abstractions, interpretation becomes much more diflcult. It is intrinsically easier to understand findings couched in symptom-distress terms than in psychosocial scales. People know the difference between hurting a little and hurting a lot. We have aimed here to transfer; via empirical analysis, some of this intuitive advantage into the psychosocial realm. In two parallel, multi-center clinical studies comparing the effects of drug treatments in hypertension and in angina, respectively, I003 patients completed, up to jive times at intervals of several weeks, a battery of psychosocial quality of life (PQOL) measure