Didactics-Sample Size

Video Transcription

Video Summary

In this video, Dr. Angelica Fletcher, a gynecologist and oncologist from the Colombian National Cancer Institute, discusses the importance of sample size in research studies. She highlights two main objectives: to be critical and analyze the quality of studies based on sample size, and to understand the role of clinicians in determining sample size. Dr. Fletcher explains that a sample is a subset of a population used to estimate what happens in the entire population. She emphasizes that studying the entire population is not feasible due to logistical and time constraints. Instead, a well-calculated sample size can provide accurate insights. Dr. Fletcher clarifies that sample size is independent of the population size and should be based on the desired absolute sample size, not the relative size. A small sample size can still accurately reflect the population if selected correctly. Dr. Fletcher discusses determinants of sample size, including hypothesis, type 1 and type 2 errors, statistical power, variability, follow-up losses, study type, and the relevance of effect size and statistical significance. She stresses the importance of understanding the clinical relevance of the effect being studied. Dr. Fletcher provides examples of how to calculate sample size using different platforms and discusses the importance of accurately defining the difference to be detected in a study. She concludes by encouraging clinicians to practice sample size calculations using available tools and to be actively involved in determining the important difference to detect in their research studies. The video was produced by Dr. Angelica Fletcher.

Asset Subtitle

Angelica Viviana Fletcher Prieto

Keywords

sample size

research studies

clinicians

population

absolute sample size

statistical power

clinical relevance