Item Response Theory Analyses of the Demonstrated Knowledge Items From the 1999Medicare Current Beneficiary Survey (Technical Note)

摘要

The purpose of this study is to assess the psychometric properties of a set ofknowledge items for possible inclusion in a Medicare beneficiary knowledge item pool. The motivation is to calibrate items that may be used to create comparable knowledge scores over time, even when the same set of items is not administered to the same set of respondents. Information Response Theory (IRT) analyses may be used to create comparable knowledge scores over time, even when the same set of items has not been administered. This approach will allow the beneficiary Medicare demonstrated-knowledge index to be adapted to changes in the Medicare program over time while consistently monitoring changes in knowledge. Using data from the Medicare Current Beneficiary Survey (MCBS) CY 1999 Access to Care and supplemental Rounds 26 & 27 (beneficiary knowledge and needs) file, a seven item beneficiary demonstrated-knowledge index was constructed. This formative research extends earlier developmental work using 1995-1998 MCBS data with the 1999 MCBS data (most recently available). The psychometric properties of the individual 7 items and the composite 7-item scale (index) were analyzed using factor analyses and IRT.