Wednesday, January 24, 2007

Designing homeworks

I'm teaching CG this semester, and it's a lot of fun to go back and read some of the older texts and papers. Preparata and Shamos is actually quite a neat book, chock full of useful tricks and techniques; if only they had better ways of describing their algorithms ...

The real challenge is designing good assignment problems, and I've almost given up on this. With the number of courses available on the web, and the amount of information accessible via Google, I'm hard pressed to write down a question that can't be solved using Google and a few keywords. Even the trick of digging up interesting lemmas from related papers doesn't work if you mention the paper in class. Or maybe I'm underestimating my students' potential desire to solve the problem themselves.


  1. Coming from the other side, as a former computational geometry student, I can say that for the vast majority of these problems, Google did not help me much at all. Solving those that I did manage to solve gave me quite a bit of satisfaction.

  2. In my experience students have problems using Google for the simplest of cases. At the moment my inbox is full of emails asking where to find information on Subversion and Latex. *sigh*

  3. I guess we all have the exact same problem when designing homework assignments. If I had to give well-known problems, I often try my best to twist it around so that Google does not return a direct hit.

    Students who do homework by Googling sometimes copy blindly a solution which has nothing to do with the question (after twisting).

    Ever since I found out about this, I have instituted the policy of 0 partial credit for solutions which solve "related" problems. :-)

  4. I use offbeat names for problems in the assignments, for example, call "minimum spanning tree" as "minsum tree subgraph problem". Students who cut and paste the problem name will not find it effective. If they instead cut and paste the entire problem description, alas, search engines don't do well with latex/pdf/formulas.

  5. I'm currently assisting a graduate algorithms course in which we don't grade the homeworks. The result is that the students have no incentive for cheating. So they really try to think about the problems independently, even if it's a lemma proved in the textbook! (Maybe Swiss students are not a good sample though!) In contrast, I've also been involved in course with graded assignments. If they can't find the solutions using a search engine, they surely find another way, coz grades matter.


Disqus for The Geomblog