Thursday, December 11, 2008

Thoughts on Comprehensive Exams, Part 2

"We think in generalities but we live in details."
-Alfred North Whitehead, British-American mathematician, physicist, and philosopher

My first post on departmental exams was focused on the theory behind those exams, however as you might guess from the quote, there is more to these exams than theory. The actual student experience with these exams varies widely from department to department - even between departments that have the same general model for their exams. The reason is that the details of what is on the exam, how it is administered, and how its results are interpreted matter to the student as much if not more than the basic reasons for having the exam. This post will attempt to give some possible responses to the three questions above in a moderately broad but probably very incomplete manner.

1) What is on the exam?
My previous post discussed this in a general sense, but here I mean how are the questions asked? Do they come from some kind of standardized question bank? Are they written by a faculty committee? Do they come directly from specific classes or are they general in nature?

At CU, comps is made up of 6 questions that all come directly from specific courses: 4 from the 4 core courses that everyone is required to take and 2 from elective courses that you have taken. For the elective questions we are actually given a set of ~6 questions from a variety of electives we may have taken with the promise that everyone will have taken at least two of the courses with questions on the list. This serves to encourage people to take more elective courses early in their studies since one could theoretically take up to 5 electives before comps and therefore have more options on the test.

These 6 questions tend to be fairly in-depth on one specific topic each, meaning that our comps is more about depth than breadth. This forces us to make sure we have a solid understanding in everything, but it also makes comps somewhat of a luck-of-the-draw process. I am currently praying that the question on my upcoming exam from Internal Processes I isn't on radiative transfer in gray atmospheres because I really hate gray atmospheres. If the question is on gray atmospheres, my score will probably be about 10% to 20% lower than if it were on something like ionization equilibrium, Zeeman splitting, or molecular transition selection rules. The opposite technique is a GRE-style test with a large number of simple questions.

2) How is it administered?
All major tests are a pain to take but the when, where, and how long are things that can vary strongly. At CU the test is given on the Friday before the start of spring semester, which this coming year is January 9th. Generally, these tests are given after a break in classes so that students have a chance to study like mad for a couple weeks beforehand. CU also does the test in two sessions on the same day, which means that we need to stay sharp for 7 hours on a single day, which is very hard to pull off. Other places have shorter tests, like Ohio State's 3 hour test. Of course this means that you cannot cover as much material.

3) How are its results interpreted?
To repeat what I said in a comment on my last post, at CU "there is no minimum score for passing and whether one passes or not depends primarily on the exam score but also on course grades and "other factors" which can include whether your score is the result of simply blowing one or two questions or preforming poorly on many questions."

"In practice, however, whether one passes or not is largely determined by exam grade. There have been a couple cases though where a student with a lower grade has passed the comps and a student with a higher grade has not, but such events are rare at CU. I know of only one in the past 4 years. In that case one individual did not pass despite scoring higher than two people who did. The faculty's rationale was that the failing student had done poorly on two core class subjects on the exam and had correspondingly low grades in both those classes, while the two passing students both had high grades in the classes that they had trouble with on the exam."


  1. Irvine's consists of three tests, each of which takes three hours given over three consecutive days. (So 9 total hours over 3 consecutive days.)

    Day 1: Classical and Statistical Mechanics
    Day 2: Quantum Mechanics
    Day 3: Electricity and Magnetism

    There is no set number of questions, just however many the writer feels can be done in 3 hours.

    The quantum portion for me was given to me on my birthday. Let's just say I have had better birthday presents. :)

  2. I would call that draconian. I thought CU's seven hour marathon was bad, but I think nine hours over three days would be worse.


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