Some courses are not as highly rated. For personnel decisions, it is essential to examine rating trends or patterns over time. Obtain a Sufficient Number of Student Raters. Classes with less than five students should probably not participate in a standardized or objective evaluation of instruction. Resulting data is likely to be unreliable and invalid.
Some researchers recommend ten as the minimum student enrollment.
For these very small classes, collecting information to open-ended questions and other comments from students may be useful. The proportion of a class that rates an instructor also is important. If over a third are absent or choose not to respond, the results may not be representative of the class. Take Into Account Course Characteristics. A few course characteristics appear to affect ratings and should be taken into account by reference to appropriate comparative data in other ways.