The Summary Statistics for SRTI Items reports show mean and percentile distributions for SRTI items for the entire campus and for each school/college. Percentiles are calculated using three academic years of SRTI results. In addition, means and percentiles are given for the four categories of student enrollment and for undergraduate and graduate courses.

Another way to avoid over-emphasizing small differences in mean scores is to assign an instructor’s SRTI means to one of 3 to 5 previously determined categories of performance (Arreola, 1995; Centra, 1993). Arreola (1995) suggests using comparison group percentile scores to determine these categories. In Figure 3, we have modified an excerpt from the 2016-18 Summary Statistics for SRTI Global Items report for undergraduate sections to define 5 categories of performance: ‘Much Lower’, ‘Lower’, ‘Similar’, ‘Higher’, and ‘Much Higher’.

A mean that falls below the 10th percentile is categorized as ‘Much Lower.’  A mean that falls somewhere between the 10th and 30th percentiles is categorized as ‘Lower’, and so on. For example, an instructor who received a mean rating of 3.9 on item 10 falls between the 30th and 40th percentiles and would be categorized as ‘Similar’. In other words, the instructor’s mean on item 10 falls in the middle 40% of means for instructors who taught undergraduate sections with 60 to 119 students enrolled during academic years 2016-18.

Figure 3: Summary Statistics - Undergraduate Sections, Academic Years 2016-18

*A percentile represents the point in a distribution at or below which a given percentage of responses fall.