Reference groups and percentiles

Reference groups 

In order to determine whether a score indicates that a student has done well or not so well, a comparison has to be made with the scores of a group of peer students, i.e. the students in the same year as the student and who took the same PGT. In ProF there are two reference groups: 1) students in the same year at the same university, and 2) all students in the same year at the other medical schools participating in the iPGT.

Percentiles

The score distribution in the reference group is presented as percentiles. Five per cent of the students score below the score level at the fifth percentile. ProF uses five percentiles: the 5th, 15th, 50th, 70th and 95th percentile. The 5th and 95th percentile indicate extremely low and extremely high scores, respectively, the 15th and 70th percentile indicate the insufficient/sufficient and the sufficient/good cut off points, respectively and the 50th percentile (median) indicates the score of the ‘average’ student.

The same colours are used in all charts to indicate the percentiles of the reference group: red for the area between the 5th and 15th percentile (weak score), blue for the area between the 15th and 70th percentile (sufficient score) and yellow for the area between the 70th and the 95th percentile (good score). The area below the red area represents extremely weak scores and the area above the yellow area represents extremely high scores. The ‘average’ score (median) is indicated by a white line in the blue area.

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