of .35 can be quite substantial. More information, and an explanation of the relationship between variance and predictive validity, can be found here. Predictive validity in modern validity theory The latest Standards for Educational and Psychological Testing reflect Samuel Messick's model of validity and do not use the term "predictive validity." Rather, the Standards describe validity-supporting "Evidence Based on Relationships [between the test scores and] Other Variables." Predictive validity involves testing a group of subjects for a certain construct, and then comparing them with results obtained at some point in the future. References Validity (statistics)