Validity in medical statistics

Validity in medical statistics and studies refers to the ability of a study to accurately measure what it is intended to measure. A valid study is one that produces results that are true and meaningful.

There are two main types of validity:

Internal validity refers to the ability of a study to establish a causal relationship between an exposure and an outcome. A study has internal validity if it is free from bias, which is any factor that can distort the results of the study. Bias can arise from a number of sources, such as the way the study is designed, the way the data is collected and analyzed, and the way the results are interpreted.

External validity refers to the ability of a study to generalize its findings to other populations and settings. A study has external validity if it is representative of the population it is intended to study. This means that the study participants should be similar to the people who will be affected by the findings of the study.

Let us review some key terms to undestand first