The National Occupational Hazard Survey (NOHS) was a nationwide observational survey conducted in a sample of nearly 5,000 establishments from 1981-1983. The goal of the NOES was to compile data on the types of potential exposure agents found at the workplace, and the kinds of safety and health programs which had been implemented at the plant level. The sample of establishments included in the survey was designed to represent those segments of American industry covered under the Occupational Safety and Health Act of 1970. This volume describes the method used to select the sample of plants to be surveyed, and the estimation techniques used to project saurvey data to national estimates.