Maps of the selected civil divisions are obtained and are partitioned by segments containing approximately the same number of households. This is generally done in New York, but for the smaller civil divisions, segmenting is generally performed in the field. One of the segments in each civil division is included in each survey. The sample is rotated from study to study. The sets used in one study generally are adjacent to those used in the next study.
Interviewers contact a designated number of households within each segment.
At each household the respondent is chosen by means of random selection pattern, geared to the number of adults of each sex who live in the household. For larger surveys utilizing the national samples, more than one national sample may be employed. This avoids having too many respondents in one cluster. In general, the maximum number of respondents in one cluster is 16. For political surveys screens are employed that eliminate unqualified persons.