has shown that the relationship between nonresponse rates and nonresponse bias is more complicated than previously believed to be true (Curtin et al., 2000; Keeter et al., 2000; Groves, 2006).

It is quite likely that response rates will continue to fall in the NCVS. If BJS attempts to keep response rates constant, it is likely that costs of the NCVS will increase. Thus, great importance should be given to determining whether low propensities to respond to the NCVS are related to different likelihoods of different types of victimizations. There are diverse methods of such nonresponse bias studies: studying the movement of victimization rates by increasing effort to measure the cases, follow-ups of samples of nonrespondents, examining changes in estimates from alternative postsurvey adjustments, and so on. These methods and others have been noted and promoted in recent U.S. Office of Management and Budget (2006b,a) guidelines for federal surveys.