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 are provided. Results: Five cases of probabilistic sampling methods and four cases of non-probabilistic sampling methods that are common are mentioned. 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 are also mentioned. Conclusion: Probabilistic sampling methods despite limiting assumptions provide more reliable results. Therefore, if it is possible, researchers should use probabilistic sampling methods to increase the accuracy of the study.