Measuring the impact of diagnostic decision support on the quality of clinical decision making: development of a reliable and valid composite score

Abstract

Objective: Few previous studies evaluating the benefits of diagnostic decision support systems have simultaneously measured changes in diagnostic quality and clinical management prompted by use of the system. This report describes a reliable and valid scoring technique to measure the quality of clinical decision plans in an acute medical setting, where diagnostic decision support tools might prove most useful.

Design: Sets of differential diagnoses and clinical management plans generated by 71 clinicians for six simulated cases, before and after decision support from a Web-based pediatric differential diagnostic tool (ISABEL), were used.

Measurements: A composite quality score was calculated separately for each diagnostic and management plan by considering the appropriateness value of each component diagnostic or management suggestion, a weighted sum of individual suggestion ratings, relevance of the entire plan, and its comprehensiveness. The reliability and validity (face, concurrent, construct, and content) of these two final scores were examined.

Results: Two hundred fifty-two diagnostic and 350 management suggestions were included in the interrater reliability analysis. There was good agreement between raters (intraclass correlation coefficient, 0.79 for diagnoses, and 0.72 for management). No counterintuitive scores were demonstrated on visual inspection of the sets. Content validity was verified by a consultation process with pediatricians. Both scores discriminated adequately between the plans of consultants and medical students and correlated well with clinicians' subjective opinions of overall plan quality (Spearman rho 0.65, p < 0.01). The diagnostic and management scores for each episode showed moderate correlation (r = 0.51).

Conclusion: The scores described can be used as key outcome measures in a larger study to fully assess the value of diagnostic decision aids, such as the ISABEL system.

Figure 1.

Scale for diagnostic suggestion ratings and proposed weighting scheme.

Figure 2.

Scale for management suggestion ratings and proposed weighting scheme.

Figure 3.

Creation of a fictitious aggregate list from panel members' and subjects' suggestions. Diagnostic suggestions are in Title case, management suggestions are in UPPER case.

Figure 4.

Example of scoring procedure for one subject's post-DDSS diagnostic and management plan.

Figure 5.

Graphical depiction of entire scoring scheme. Rectangles represent tasks and measurements, ovals represent actions, and the diamond represents a simple task such as tallying. The gray shaded oval indicates a step that did not directly contribute to the procedure. Adapted with permission from: Hripcsak G, Wilcox A. Reference standards, judges, and comparison subjects: roles for experts in evaluating system performance. J Am Med Inform Assoc. 2002;9:1–15.

Figure 6.

Concurrent validity: correlation between DQS/MQS and overall subjective score.

Figure 7.

Correlation between DQS and MQS.

Figure 8.

Concurrent validity assessed after the omission of weighting and relevance steps.