This course will discuss what mixed models are, why they are called "mixed" models, what is a "random factor", and why. The primary focus will be for the researcher to understand when he or she should ...

This is a graduate-level course on multilevel modeling, a popular statistical approach in social, behavioral, and health sciences research. Multilevel modeling, also known as hierarchical linear ...

Earlier (Wainer & Lewis, 1990), we reported the initial development of a testlet-based algebra test. In this account, we provide the details of this excursion into the use of testlets. A pretest of ...