Psychometric theory is a well-recognized approach for developing psychological measurement and standardized education tests (Kim-O & Embretson, 2010). It can be divided into two categories: classical test theory (CTT) and item response theory (IRT). CTT was pioneered a century ago by Spearman, while IRT developed in the 1950s and 1960s.
Kim-O and Embretson (2010) provided a thorough discussion of IRT and why it has become the preferred approach. In the CTT model, estimates of examinees’ true test scores are often linear transformations of the raw test score, and are related to relevant normative populations by the transformation. Alternative test forms can be used to estimate true scores if the forms are parallel tests with the same expected true scores and error distributions. Psychometric indices for items in CTT are related to the properties of the test scores, particularly reliability and variance. In other words, item difficulty is defined...
References and Readings
- Kiernan, M., Moore, S. D., & Schoffman, D. E. (2011) Social support for healthy behaviors: Scale psychometrics and prediction of weight loss among women in a behavioral program. Obesity (Silver Spring, MD) Oct, 13th [Epub ahead of print].Google Scholar
- Kowalchuk Horn, K., Jennings, S., Richardson, G., et al. (2012). The patient-specific functional scale: Psychometrics, clinimetrics, and application as a clinical outcome measure. The Journal of Orthopaedic and Sports Physical Therapy, 42(1), 30–42.Google Scholar
- Maddux, R. E., Lundh, L. G., & Bäckström, M. (2011). The Swedish depressive personality disorder inventory: Psychometrics and clinical correlates from a DSM-IV and proposed DSM-5 perspective. Nordic Journal of Psychiatry, Sep 22nd [epub ahead of print].Google Scholar