Validating household reports of health care use in the medical expenditure panel survey.

The Medical Expenditure Panel Survey (MEPS) is a widely used nationally representative survey of the levels and determinants of health care use and spending by U.S. households. Before its inception in 1996, these data were collected decennially in the 1987 National Medical Expenditure Survey and the 1977 National Medical Care Expenditure Survey, but the need for more timely data led to the significant public investment of an annual expenditure survey. The MEPS collects detailed information from households about their use of office-based and hospital services, prescription drugs, and other health care services. The household-reported use is the basis for national estimates of health care expenditures, but reliance on household-reported utilization raises concerns about the accuracy of the estimates. A recent review of 42 studies evaluating the accuracy of self-reported utilization data found that the most common problem is underreporting (Bhandari and Wagner 2006). However, these studies provide mixed and sometimes conflicting evidence about the extent of underreporting. Some studies found relatively little underreporting error for physician visits (Cleary and Jette 1984; Roberts et al. 1996; Raina et al. 1998; Lubeck and Hubert 2005;), inpatient stays (Roberts et al. 1996; Lubeck and Hubert 2005;), and emergency room visits (Lubeck and Hubert 2005). Other studies found relatively large underreporting in some or all types of visits (Glandon, Counte, and Tancredi 1992; Ungar, Coyte, and the Pharmacy Medication Monitoring Program Advisory Board 1998; Wallihan, Stump, and Callahan 1999; Rozario, Morrow-Howell, and Proctor 2004;). Another found overreporting of emergency room visits (Ritter et al. 2001). In a more recent study, Wolinsky et al. (2007) used Medicare claims for respondents in the Survey on Assets and Health Dynamics among the Oldest Old (AHEAD) to validate the accuracy of self-reported hospital stays and physician visits for evaluation and management services. Concordance was high for self-reported hospital stays and Medicare claims, but low for physician visits. Together these findings shed little light on underreporting in the MEPS, even though it is likely a major contributing factor to the estimated gap of 14 percent in benchmark comparisons of MEPS to the National Health Care Expenditure Accounts (Sing et al. 2006). In general, we would expect more reliable reporting in the MEPS compared with AHEAD and many other national surveys, because MEPS uses a relatively short recall period (5 months on average versus 12 months), diaries, and extensive probes to enhance recall (Cohen et al. 1996/1997). However, the MEPS relies on one household informant to report health care use for all household members (i.e., they are a household proxy) and, in rare instances, uses proxies outside of the household. Like the Wolinsky et al. (2007) study, we use Medicare claims to assess the accuracy of household-reported office-based and hospital care for a sample of Medicare beneficiaries in the MEPS. While not an absolute gold standard, we similarly presume that Medicare claims represent a complete record of the services paid for by Medicare. Because we also restrict attention in MEPS to visits and stays paid by Medicare, these claims serve as an appropriate benchmark. Our MEPS sample includes Medicare beneficiaries who reported utilization for themselves, as well as beneficiaries for whom either a resident or nonresident proxy reported their health care use. All three are important to understanding the accuracy of MEPS utilization data. Besides assessing the level of concordance between MEPS utilization data and Medicare claims, we seek to understand and quantify the extent to which differential reporting by population subgroups affects descriptive and behavioral analyses such as Aday–Andersen (1974) models of health care utilization. In doing so, we build on existing studies that tend to focus principally on the assessment of concordance.