In this article, authors Jean Abraham, Pinar Karaca-Mandic, and Michel Boudreaux, generate national-, regional-, and state-level estimates of the individual health insurance market using multiple federal surveys and administrative data from the National Association of Insurance Commissioners (NAIC).  They find that notable differences exist between survey estimates themselves and between survey estimates and NAIC administrative counts.

NAIC data for this study were purchased through a grant to SHADAC from the Robert Wood Johnson Foundation's State Network initiative.  

Abraham, J.M., Karaca-Mandic, P., & Boudreaux, M. 2013. "Sizing Up the Individual Market for Health Insurance: A Comparison of Survey and Administrative Data Sources." Medical Care Research and Review 70(4): 418-433.