The sample of public and private employers in the four county area was selected by classifying all employers into categories or strata based on the number of employees. These were sampled at varying rates with greater emphasis given larger employers. All employers selected were sent a questionnaire, and follow-up phone calls were made to all non-respondents.
DiMartino, David R., "Analysis of Employer Attitudes and Needs for MCC" (1980). Publications Archives, 1963-2000. 129.