The TRACE System - Sample Selection
 
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  • Using demographic data provided by the school, each graduate is assigned to an appropriate cell (stratum) in the sampling matrix defined by gender, ethnic/racial group, and GPA.
  • A statistical profile of the Class is developed and a mathematical algorithm calculates the number of respondents required to provide statistically accurate data. A preliminary random sample of graduates is selected from each cell.
  • To compensate for response-rate differences among the graduate strata, empirical oversampling weights are applied to each cell and the preliminary cell samples are appropriately enlarged. The final total sample is composed of the weighted, individual stratum samples.
  • Samples can be further refined to ensure that programs of special interest or concern are proportionately represented.
  • For longitudinal studies ranging to five years post-graduation, samples are further enlarged to offset lower response rates attributable to population mobility and related factors.
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Sample Selection
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