An empirical assessment of the validity of explicit and implicit process-of-care criteria for quality assessment

OBJECTIVE. To evaluate the validity of three criteria-based methods of quality assessment: unit weighted explicit process-of-care criteria; differentially weighted explicit process-of-care criteria; and structured implicit process-of-care criteria. METHODS. The three methods were applied to records of index hospitalizations in a study of unplanned readmission involving roughly 2,500 patients with one of three diagnoses treated at 12 Veterans Affairs hospitals. Convergent validity among the three methods was estimated using Spearman rank correlation. Predictive validity was evaluated by comparing process-of-care scores between patients who were or were not subsequently readmitted within 14 days. RESULTS. The three methods displayed high convergent validity and substantial predictive validity. Index-stay mean scores, using explicit criteria, were generally lower in patients subsequently readmitted, and differences between readmitted and nonreadmitted patients achieved statistical significance as follows: mean readiness-for-discharge scores were significantly lower in patients with heart failure or with diabetes who were readmitted; and mean admission work-up scores were significantly lower in patients with lung disease who were readmitted. Scores derived from the structured implicit review were lower in patients eventually readmitted but significantly so only in diabetics. CONCLUSIONS. These three criteria-based methods of assessing process of care appear to be measuring the same construct, presumably "quality of care." Both the explicit and implicit methods had substantial validity, but the explicit method is preferable. In this study, as in others, it had greater inter-rater reliability.