Trends in Premiums in the Small Group and Individual Insurance Markets, 2008-2011. Methods


We compiled and analyzed data on rate increase filings for comprehensive major medical insurance products available from a sample of states. The total number of filings in the database is 2,809, of which 1,923 are from the individual/conversion market and 886 from the small group market.

We compiled data on rate filings from a number of sources, including photocopies made in person at state insurance departments and the use of public websites that provided documentation of premium rate increase filings in states where this resource was available. Many websites accessed became available only during the course of the study. During the study NORC discovered and documented several shortcomings in both the availability and quality of the filings necessary to answer the research questions. For example, the Illinois Department of Insurance produced a summary of recent rate increases in the individual market since 2005, but has not updated the information available since October 2010. In some states, such as Colorado, documentation captured from different sources produced data sets with discrepancies that were difficult to reconcile, as no source was clearly authoritative. Many filings we found were incomplete, missing information about product type, enrollment, or disposition following state regulatory review. These data limitations and others are discussed in more detail in the main body of the report and should be considered carefully when interpreting the study’s results.

We developed sample weights using data from the National Association of Insurance Commissioners (NAIC), the Medical Expenditure Panel Survey Insurance Component2 (MEPS-IC), and the filings themselves, to calculate national and state averages. When enrollment data were missing from filings, imputation methods were employed to populate those data. NORC conducted sensitivity analyses to assess how modifications in the approach to weighting or other decision criteria would impact the findings. We concluded that, had we made alternative decisions for weighting and exclusions, the resulting changes in our point estimates would not change the major findings or conclusions of the study.

2 The Medical Expenditure Panel Survey (MEPS) is conducted by AHRQ annually; the Insurance Component (MEPS-IC) draws a sample from both private and public-sector employers and surveys them on the health insurance coverage they offer.

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