Thursday, September 24, 2015

Should course pre-requisites be enforced?

This is a question that is sometimes discussed.
Can you study physics (biochemistry) if you have not taken a calculus (chemistry) course?
Should you be allowed to?

At UQ we actually have some solid data that allows a more meaningful discussion about the issue. The following text is taken from a recent review of the Bachelor of Science at UQ (page 125).
As some, but by no means all, students are aware, for about 15 years the university has not enforced completion of prerequisites. That is, students are free to enrol in any courses they choose, irrespective of whether or not they have previously enrolled in, or passed, any prerequisites.  Students generally are not actively advised that prerequisites are effectively optional. However, any student who explicitly asks is usually advised to complete prerequisites, and that they take a significant risk if they attempt a course without the necessary background knowledge. The lack of enforcement of prerequisites means that a significant number of students ignore the advice to complete prerequisites and proceed with advanced courses without having done the prerequisite(s). 
This results in difficulties for academics teaching the advanced courses and for the students attempting to catch up on the knowledge and/or skills they lack. There is also some concern about a duty of care to students: should they be allowed to enter a course without having completed a prerequisite when data suggest that a significant number will fail? This issue may become even more prominent in a deregulated market, with higher fees. A counter argument to this is that students can and should take responsibility for their own decisions. Provided the advice they receive is accurate, timely and clear, they can decide for themselves whether or not to follow the advice. 
To help answer the question of whether or not prerequisites should be enforced, an analysis of a number of second and third year courses was undertaken. Figure 114 shows student failure rates in such courses, broken down by whether or not students had completed the recommended prerequisite courses(s).
The data show that the proportion of students attempting these courses without having completed the prerequisites ranges from 14% to 34%, with the average around 25%. There is a clear advantage to having completed the prerequisite, with lower failure rates amongst such students in all courses. Despite this, on average, 75% of the students who have not completed a prerequisite passed the follow-on course. In all cases, more than 50% of such students passed the course. In one case, almost 90% of such students passed the course.
This puts a somewhat positive spin on the problem. I think the fact that in many of the courses 30-40% of the students without the pre-requisite failed is a concern. A lot of time (both student and teacher) is being wasted. In particular, I know faculty who are frustrated by the demands, complaints, and questions of students who have not taken pre-requisites.

I don't have a strong view on this. I think skipping a pre-requisite is o.k. for gifted and motivated students who fully understand they will have to do significant work. However, for most students, particularly mediocre ones, I think it is a bad idea. Thus, I think pre-requisites should only be waived on a case-by-case basis. Unfortunately, that is labour intensive.

What about other institutions?
Based on a brief literature search I only found one paper that had looked at the issue.
Minimal Impact of Organic Chemistry Prerequisite on Student Performance in Introductory Biochemistry.

What do you think? Should pre-requisites be enforced?


  1. I have a pretty strong opinion on this. :)

    At the institution where I did my undergraduate degree, the major programs (chemistry/physics/whatever) were pretty highly structured, and the programs themselves had many required courses. Only about 10-20% of courses were free to choose by the student, depending on your program.

    This meant that it was relatively rare for a student to e.g. try taking biochemistry without taking the requisite organic chemistry, because BOTH courses were already required by the overall program. Since the number of elective courses was somewhat low, taking courses well outside your area of knowledge was less prominent - students would rather sit in and listen to lectures rather than take the courses officially.

    If you wanted to take a course without having the prerequisite, you needed specific permission of the instructor, and also your program advisor, which meant the rare cases where this was requested were considered on a case-by-case basis. Most students who went through the whole process had good reason, so the decisions were easy, and not laborious for the instructors. By far the most common reason for such an override was because the student had taken a course SIMILAR to the prerequisite, but perhaps in a different department (e.g. calculus for math majors vs. physics majors). Motivated students could still take courses without even equivalent prerequisites (and I did), but always with a strong warning, "At your own risk - don't ask for extra help - you are responsible."

    There was also a rule that all courses added beyond your normal program load were free of cost. This meant that you could take (or officially audit) any number of extra courses completely for free. Instead of taking a physics course without calculus, and suffer the extra workload of learning on their own, students were encouraged to take the calculus in a previous semester as an extra course for free, and benefit from an actual instructor.

    Personally, I think this is a good system. I don't see the motivation for undergraduate students to skip prerequisite courses anyway. What is to be gained? This only creates gaps in their knowledge, and most undergrads are not mature enough in their careers to identify what knowledge they will need later (either during their degree or after). There is too strong a temptation to skip "hard" courses if they don't seem useful at the time. Perhaps a high grade in biochemistry is possible without organic, but can you say the same for solid state physics without the requisite statistical mechanics? Are undergrads knowledgeable enough to make such choices?

    Overall, the purpose of any undergrad degree is to get a broad base of knowledge that is, in some sense, standardized - employers and academics have an expectation of the students' knowledge if they obtain a certain degree, or have a certain course on their transcript. It is usually to the benefit of the students to take the courses that are "suggested" by the prerequisites, because this is what the world expects them to know. Getting a good grade in a specific course is not the ultimate metric that you are measured by.

    1. Dear Steve,

      Thanks for sharing your experience and expressing you view.
      I particularly appreciate your idealism.

      My only moderating response is that we need to acknowledge that this issue has to be worked out in the context of the institution: its resources and the quality of its students. It sounds like you were at a "high end" institution.
      Stanford, San Jose State, University of Queensland, and University of Lagos are not the same! I don't think the same policy is going to be realistic or workable for all of them.