The educational goals of WeBWorK
WeBWorK is not an attempt at Computer Assisted Instruction in the usual sense. The program does not teach, it merely gives immediate feedback as to whether or not the student has submitted the correct answer. If the student is unable to find and correct their mistake in a reasonable amount of time, the student is encouraged to seek help elsewhere, from fellow students, from the TAs or from the instructor (either in person or via e-mail). It would be possible to provide hints based on the type of wrong answer, but, at least at the moment, it is unclear that this would help the learning process. It seems preferable to us that when a student is having difficulty they be encouraged to seek help from humans.
Some observations on the educational effects of WeBWorK.
There is no doubt, from anecdotal evidence alone, that using WeBWorK changes the social workings of the classroom. Students frequently work together to find answers to "tough" questions that no one seems to be getting the computer to accept. Occasionally they can show that they are right and the computer is wrong. The lively e-mail correspondence between the student and instructor encouraged by WeBWorK testifies to a new dynamic in the learning process. A new communications and learning channel between students and instructors has been created.
Most students (more than 80%) get all of the answers correct eventually. Because the problems are individualized they have almost certainly had to learn something about the problem, since they cannot merely copy answers from another student. They can learn a general method for solving the problem from another student, but at this stage that is what we are trying to teach them! This is better than a common approach of attempting a problem, but being satisfied with the attempt whether or not it achieves the correct answer.
Another anecdotal observation from both CAPA and WeBWorK is that students are much more focused in the questions they ask TA's and professors. Usually there is a specific part of a problem causing them difficulty and since they have (almost always) worked hard on the problem, they are more likely to really understand the instructor's explanation.
Finally, by giving WeBWorK exams where students receive partial credit for successfully answering on WeBWorK questions they missed on the regular in class exam, it is possible to turn exams into a powerful learning experience while at the same time giving students a "second" chance to do better on exams.