When it comes to the transition from high school to university, an oft-quoted line is that “student averages tend to drop about 10-15%”. Looking at the basic numbers, this initially seems to be a pretty fair statement. For example, at York University, you need at least a mid to high 70s average to receive admission to one of its science programs, such as Biology (e.g. 77+ or so).
Considering several factors, such as the fact that fewer students probably got a 90+ average than the number of students who achieved a 77-89 average, it is probably safe to assume that if we computed the average of the final high school grades for a first year York science class, the number would be around 85. And I would imagine that most first year university science classes are made of students with similar high school marks.
Looking at the first year university science courses I have taken so far, the class averages have generally been around the ~65 mark, so it seems that on average, student marks do drop about 15%, and possibly more in some cases.
However, keep in mind this doesn’t mean that all students tend to drop 10-15% in their course marks; it just means that on average, students seem to achieve lower marks than they did in high school. Initially this seems to make sense: if a university class still needs to maintain a class average of 65, then obviously an entering class with high school averages of 85 should see a drop. As a matter of fact, however, the issue is much deeper and complex than this.
Consider the fact that there are actually some students who do better in university science than in high school. There are also some students, unfortunately, who do worse. And there are students who do about the same.
Moreover, there isn’t an obvious correlation between high school marks and university marks. For example, I know a student with a 95 high school average who now maintains a mid-80’s average in university, and can’t seem to break the 90 barrier. On the other hand, I know another student with a 95 high school average who completed first year university science with an even higher average. Myself, I had about a 94 final high school average and my first year university average was somewhere close to that.
NOTE: Universities generally use a GPA system which does not involve the averaging of numerical grades – rather, each numerical grade for a course is first converted to a value on the GPA scale, and these GPA values are then averaged. I’m just trying to make a point with my previous few statements.
Clearly, at least for science programs, the transition between years within high school (where students maintain the same type of marks) is very different from the transition from high school to university.