A Comparison of Marking Levels in the Reviewed Majors

These differences in the distribution of grades can be attributed in part to the different levels of academic ability among the students attracted to the various majors.

It’s possible to adjust individual unit marks for the effect of general academic ability using the method detailed at the end of this document. Majors can then be compared with reference to the implied distribution of grades had all students achieved the average UWA Entry Score associated with enrolments in these majors.

It’s also possible to compare these majors with reference to the course average mark (WAM) calculated for a student with that sample average UWA Entry Score (shown right). On the next slide this value has been plotted against the average UWA Entry Score associated with unit enrolments in the same majors, revealing a strong negative correlation (r 2 = 0.64) between these two metrics.

On average, a student who undertakes a major that attracts a higher proportion of more academically capable students will obtain a lower course average mark than if they’d undertaken a major that attracts a lower proportion of those students. The implication is that these marking distributions are, in effect, being normalised independently (i.e. within course units or disciplines) without reference to differences in the average academic ability of the students who nominate the various majors.

The same inverse correlation appears when marks are averaged within the faculties that own units within these majors; lower marks being awarded within faculties whose units attract students with higher general academic ability. MDHS is a notable exception here, falling instead along the reference curve derived from student performance in broadening units (as detailed below). Professional accreditation requirements may be serving to anchor marking levels in medicine to external standards. Broadening Units Reference Curve

Adjusting for General Academic Ability: Notes On Methodology

Very broadly, a student’s mark in a given course unit is a function of their general academic ability and of the relevant knowledge and skills they’ve accumulated through cognate studies. By selectively focusing on performance in broadening enrolments – i.e. on the marks obtained where students will, on average, have had less experience of related disciplines – it’s possible to more effectively isolate the relationship between unit marks and general academic ability. At UWA the administrative processes aimed at standardising marking across course units operate primarily within individual Business Units (BUs). The distribution of the average broadening unit mark awarded by each BU was plotted against the average UWA Entry Score of students enrolled in those units (as shown right), and a simple linear regression curve (the dashed line) was fitted to estimate the rate of change in Unit Mark as a function of UWA Entry Score. This “Broadening Unit Reference Curve” accounted for 66% of the variation in the average unit mark awarded by BUs. Note that the values presented for both Unit Mark and UWA Entry Score extend well into the non-linear upper range of binomial frequencies, and that an angular transformation – asin(√p) – has been applied in each case to equalise variance over the wider range of values prior to fitting curves or calculating the averages reported.

The Broadening Unit Reference Curve (dashed line) is a reasonable fit to the observed relationship between UWA Entry Score and Unit Mark for individual students, as illustrated here and in the following slides for Level 1 students enrolled in units owned by various Business Units or Faculties.

Where marks diverge systematically from the reference curve the displacement under the angular transform is essentially constant with respect to UWA Entry Score. It’s possible, then, to adjust Unit Marks for general academic ability by simply adding the residual about the reference curve to a fixed value; nominally the mark predicted for the average UWA Entry Score associated with unit enrolments in the reviewed majors (i.e. 92.1%, corresponding to 73.7 o under the asin(√p) transform).

The Broadening Unit Reference Curve (dashed line) is also a reasonable match to the relationship between the average UWA Entry Score of students enrolled in a course unit and the average mark awarded in that unit (solid line), as illustrated here for the subset of units owned by the Faculty of Science. The unit mark predicted for a student with the sample’s average UWA Entry Score was calculated for each course unit using the method described above. Those unit marks were then averaged across all unit enrolments in the various majors to produce the predicted WAM values presented at the head of this document.