The current set of three studies further evaluates the validity and application of the Psychological Research Inventory of Concepts (PRIC). In Study 1, we administered the PRIC to a sample of introductory psychology students and online (Mechanical Turk) participants along with measures assessing theoretically related concepts. We found evidence of concurrent validity by demonstrating that PRIC scores relate to education, cognitive effort, and general psychological knowledge. In Study 2, we demonstrated that advanced psychology majors score higher on the PRIC than college graduates who did not major in psychology, suggesting that the PRIC assesses domain-specific knowledge and may be useful in assessment of the undergraduate psychology major. Finally, in Study 3, we demonstrated that scores on the PRIC increase from the start to the end of a research methods course. Together, these studies provide further evidence that the PRIC may be a useful index of learning research methods and statistical knowledge important for the undergraduate psychology degree.