Comparison of Approaches for Aggregating Quality Measures in Population-based Payment Models

To assess the impact of alternative methods of aggregating individual quality measures on Accountable Care Organization (ACO) overall scores.

2014 quality scores for Medicare ACOs.

We compare ACO overall scores derived using CMS' aggregation approach to those derived using alternative approaches to grouping and weighting measures.

Alternative grouping and weighting methods based on statistical criteria produced overall quality scores similar to those produced using CMS' approach (κ = 0.80 to 0.95). Scores derived from giving specific domains greater weight were less similar (κ = 0.51 to 0.93).

How measures are grouped into domains and how these domains are weighted to generate overall scores can have important implications for ACO's shared savings payments.