Background: Economic analyses are increasingly important in medical research. Accuracy often requires that they include large, diverse populations, which requires data from multiple sources. The difficulty is in making the data comparable across different settings. This article focuses on how to create comparable measures of health care resource use and cost using data from seven health plans and delivery systems participating in the Cancer Research Network's HMOs Investigating Tobacco study.
Methods: We used a data inventory to identify variation in data capture across sites and used data dictionaries to develop algorithms for assigning standardized cost to the three major components of health care use: outpatient, inpatient, and pharmacy.
Results: The plans included in this study varied from fully integrated, closed-panel models to plans and delivery systems that include network or independent physician association components. Information derived from the data inventory and data dictionary instruments demonstrated a substantial variation in both the content and capture of data across all sites and across all components of usage. The methods we employed for cost allocation varied by usage component and were based on our ability to leverage the data points available to best reflect actual resource use.
Conclusions: The importance of this article is the method of ascertaining, cataloging, and addressing the within- and between-plan differences in health care resource use. Second, the decisions we made to address the differences between health plans provide other researchers a starting point when creating a cost algorithm for multisite retrospective research.