In order to evaluate their programs, Extension offices have to gather evidence about program outcomes and impacts. The first step of this process is to determine the appropriate amount of data needed, or the correct sample size. Using a sample can help Extension professionals save time, money, and labor because fewer people must be interviewed or surveyed; thus the complete set of data can be collected quickly. This revised 9-page fact sheet provides an overview of sampling procedures, beginning with how to determine the research problem, define the population, and decide whether to sample, and going on to explain the different types of samples and how they are used. Written by Glenn D. Israel, and published by the Agricultural Education and Communication Department, December 2015.
Dillman, D. A., J. D. Smyth, & L. M. Christian. (2014). Internet, phone, mail, and mixed-mode surveys: The tailored design method. (4th ed.). Hoboken, NJ: John Wiley and Sons.
Ilvento, Thomas W., Paul D. Warner & Richard C. Maurer. (1986). Sampling Issues for Evaluations in the Cooperative Extension Service. Kentucky Cooperative Extension Service. University of Kentucky.
Kish, Leslie. (1965). Survey Sampling. New York: John Wiley and Sons, Inc.
Slonim, M. J. (1957). "Sampling in a Nutshell," American Statistical Association Journal. June. https://doi.org/10.1080/01621459.1957.10501375
Smith, M. F. (1983). Sampling Considerations In Evaluating Cooperative Extension Programs. Florida Cooperative Extension Service Bulletin PE-1. Institute of Food and Agricultural Sciences. University of Florida.
Sudman, Seymour. (1976). Applied Sampling. New York: Academic Press.