This document discusses different types of data validity including face validity, content validity, criterion validity (predictive validity, concurrent validity, discriminant validity), external validity, internal validity, ecological validity, and population validity. It provides examples and definitions for each type of validity. Additionally, it outlines factors that can affect data validity such as history, maturation, testing, instrumentation, and selection bias. Validity is determined through empirical evidence over multiple studies and is not an all-or-none concept but rather exists on a continuum.