Reporting of drug expenditures in the MCBS.

Comparing data from both the 1999 MCBS and drug utilization data supplied by the survey respondents' pharmacies, the author details the methods used to determine the level of misreporting of drug expenditures in the MCBS. Findings suggest that prescription drug expenditures are underreported by 17 percent and the number of prescriptions used is underreported by 17.7 percent. The data also identify demographic factors that predict a beneficiary's likelihood to either overreport or underreport his or her medications, as well as the extent to which beneficiaries misreport their drug use and spending.