Copyright (c) 2026 Liliam Avila
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Knowing whether a research project requires a sample and calculating its size is essential knowledge for every researcher starting out in the field. First, it's crucial to determine if sampling is necessary, which requires a solid understanding of the concepts of universe, study population, and sample. Second, it's essential to establish the appropriate sampling method based on the type of study being conducted. Finally, a practical tool for carrying out the sampling process is necessary.
This article presents these three points, offering a practical approach to planning observational research using the free software tool, Open Epi. It provides guidance based on the type of observational study being conducted, whether descriptive or analytical (cross-sectional, cohort, or case-control).
