Tuesday, October 27, 2009

More Tests?

If the aim of assessment is to assess the true ability of a student, then from a statistical point of view, it is better to have more small tests rather than a single big exam.

First, assume that we are using some consistent estimator of a student's ability. The natural conclusion of this assumption is that the more tests we conduct, the more likely it is that the estimate will be close to the true value.

The argument is also intuitive; with more elements of assessment, the impact of a "freak event" that affects student performance is greatly reduced. The result is hence more likely to reflect the true performance of the student, and is fairer due to the reduced role of luck.

No comments: