Here is an overview on the main types of validity used for the scientific method.
"Any research can be affected by different kinds of factors which, while extraneous to the concerns of the research, can invalidate the findings" (Seliger & Shohamy 1989, 95).
Let's take a look on the the most frequent uses of validity in the scientific method:
“Could there be an alternative cause, or causes, that explain my observations and results?”
Test validity is an indicator of how much meaning can be placed upon a set of test results.
Criterion Validity assesses whether a test reflects a certain set of abilities.
Content validity is the estimate of how much a measure represents every single element of a construct.
Construct validity defines how well a test or experiment measures up to its claims. A test designed to measure depression must only measure that particular construct, not closely related ideals such as anxiety or stress.
Face validity is a measure of how representative a research project is ‘at face value,' and whether it appears to be a good project.