te the sample subjects.
Once the four lists of policemen, prosecutors, judges, and local politicians have been drawn up, the survey will be sent to the names on the list, along with a self-addressed, stamped envelope and a cover letter explaining the nature of the study and emphasizing the importance of respondents returning their completed instruments. After two weeks have passed, the investigator will determine which respondents have not returned their completed instruments.
A second mailing of the survey instrument will then be sent to respondents, along with another cover letter which again emphasizes the importance of returning completed instruments. Once another two weeks have passed, the investigator will again assess for respondents who have not returned their surveys. The investigator will then contact by telephone those respondents who have not returned the surveys. Once again, the need for completed instruments will be emphasized; and, if necessary, the investigator will send a third mailing of the survey instrument to these respondents.
The purpose for the second and third follow-up procedures is to ensure that the sample size of those returning instruments reaches at least the 40 to 60 percent return rate which, according to Borg and Gall, is necessary if survey data is to be unbiased. According to these authors, when survey data has less than a 40 percent return rate, there is an increased likelihood that sample data will represent only extreme opinions or view
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