Mounting evidence for response shifts in quality of life (QOL) appraisal indicates the need to include direct measurement of the appraisal process itself as a necessary part of QOL assessment. We propose that directly assessing QOL appraisal processes will not only improve our ability to interpret QOL scores in the traditional sense, but will also yield a deeper understanding of the appraisal process in the attribution of and divergence in meaning. The published evidence for response shift is reviewed, and an assessment paradigm is proposed that includes the explicit measurement of QOL appraisal process parameters: 1) induction of a frame of reference; 2) recall and sampling of salient experiences; 3) standards of comparison used to appraise experiences; and 4) subjective algorithm used to prioritize and combine appraisals to arrive at a QOL rating. A QOL Appraisal Profile, which measures key appraisal processes, is introduced as an adjunct to existing QOL scales. The proposed theoretical model, building on the Sprangers and Schwartz (1999) model and highlighting appraisal processes, provides a fully testable theoretical treatment of QOL and change in QOL, suggesting hypothesized causal relationships and explanatory pathways for both cross-sectional and longitudinal QOL research.