Final Report on the Effects of Sample Attrition on Estimates of Channeling's Impacts. V. ESTIMATES OF ATTRITION BIAS USING THE STATISTICAL CORRECTION PROCEDURES


The evidence presented in the previous chapter indicated that estimates of hospital impacts in the evaluation, based on the Medicare sample, are not biased by attrition. The evidence for other outcomes and analysis samples, while suggesting that attrition did not lead to biased estimates of impacts, was less direct, however. Hence, in this chapter we employ the statistical procedures described in Chapter III to provide additional evidence on whether restriction of the analysis of channeling impacts to the nursing home, followup, and in-community samples produces biased estimates of channeling impacts.

In Section A below we present the model of attrition estimated for the nursing home, followup, and in-community samples. Because of the central importance of the interviews in defining all of these samples, the discussion is focused on attrition from the followup sample. In Section B, estimates of channeling impacts corrected for potential attrition bias, using the methods of Chapter III, are compared to impact estimates unadjusted for bias. In Section C, the approach developed in Chapter III is extended to make it more general, and these more general results are compared to those obtained from the simpler model.

View full report


"atritn.pdf" (pdf, 4.74Mb)

Note: Documents in PDF format require the Adobe Acrobat Reader®. If you experience problems with PDF documents, please download the latest version of the Reader®