A study was conducted to determine the extent and nature on non-respondent bias in the follow-up survey in 1981 of Michigan secondary vocational education students from the class of 1980. The response rate to the annual survey has been approximately 76 percent in past years, yet there remains a significant non-response bias potential. This study, therefore, addresses the degree of similarity of certain demographic and status measures between those former students who responded to the follow-up survey in 1981 and those who did not. A representative sample of non-respondents was identified, and these subjects were asked the same questions that appear in the original survey instrument. The results of the non-responder sample were then compared with the data obtained from students who responded to the original survey. Three major conclusions were drawn from the study: (1) district educators responsible for the follow-up did, for the most part, successfully follow-up their completers and leavers, as was evident from the high return rate on the difficult task of obtaining complete information on 1,600 non-responders; (2) the information obtained from the respondents is a highly accurate estimate of the status of the universe of former vocational students surveyed, on most of the survey items; (3) the data from the sample of non-respondents surveyed revealed certain areas of non-respondent bias which should be considered in the interpretation and reporting of the survey results if the universe is to be all completers and leavers rather than only those who are willing to complete the follow-up survey. (KC)