Weighted item response rates were calculated for all variables used in this report. The weighted item response rates were calculated by dividing the weighted number of valid responses by the weighted population for which the item was applicable. Overall, most of the items had a high response rate. Items with weighted item response rates below 90 percent are shown in table B-1. Three variables had item response rates below 85 percent. For the three NELS:88/01 variables (ACCURHSQ, HIGHMATH, GPA), the low weighted response rate is due in large part to unavailable high school transcript data. For these variables, an analysis of item nonrespondents was conducted and no differences could be detected between respondents and nonrespondents in percentage who were female.