The National Longitudinal Study of the High School Class of 1972 obtained data for 23,451 students, of whom 16,683 completed the base-year questionnaire; 21,350 completed the first follow-up; and 20,872 completed the second follow-up. This report describes the methodology for minimizing bias in the data which might be caused by nonresponse to such a large survey. A weighting class method was selected that involved partitioning the entire sample into classes of presumably homogeneous students. This report describes the second follow-up weight calculations, nonresponse adjustment methodology, classifier variable data, procedure for forming weighting classes, and the adjusted student weight calculations. The appended tables show the nonresponse adjustment factors for each weighting class as well as the total number of students, total number of responding students, the sum of all unadjusted weights, and the sum of the respondent unadjusted weights for each weighting class. (Author/CTM)