This document provides guidance on determining appropriate sample sizes based on population size. It states that for populations under 100, the entire population should be surveyed. For populations around 500, a sample size of 50% is recommended, while for populations around 1,500, a sample size of 20% is recommended. Beyond a population of 5,000, a sample size of 400 may be adequate regardless of total population size. The document also provides a table comparing strengths and weaknesses of different sampling techniques, including probability and non-probability methods.