A beginner's guide to sampling methods in medical research

Background: Sampling methods are one of the main components of each research. Familiarity with a variety of sampling methods is essential for researchers.Objective: The main purpose of this study was to teach different probabilistic and non-probabilistic sampling methods to improve the knowledge of researchers in conducting more accurate research.Methods: In this tutorial article, useful information about each sampling method, as well as how to properly use each method and its strengths and weaknesses were provided.Results: Five cases of probabilistic sampling methods and four cases of non-probabilistic sampling methods that are common were taught. Probabilistic sampling included simple random sampling, stratified random sampling, cluster sampling, systematic random sampling, and multi-stage random sampling. In addition to introducing each method, its strengths and weaknesses were also mentioned.Conclusion: Probabilistic sampling methods despite limiting assumptions provide more reliable results. Therefore, if it is possible, researchers should use probabilistic sampling methods for the accuracy of the study.