Diagnostic testing prior to registration into a credit course is not a new concept. It's probably most well known in the language arts. For example, testing a student on their oral abilities in their second language with a short interview can quickly allow the professor to recommend which level of course to enrol in. In distance education, one can still do this! There are many examples of this and they can vary in technical complexity from simple self-grading of text-based answers to fully automated graded testing including media such as figures and graphs. Either way works well and accomplishes the goal.
For example, visit the DCE050: Essential Writing Skills course description at the Royal Military College of Canada. On this page is a link to a text-based "threshold test" that students take at their own pace and then they download an answer key to self-grade the test. The course administrator then goes on to write: "If you score below 70% (35 out of 50) on this Threshold Test, we recommend that you enrol in DCE 050 – Essential Writing Skills." Simple to use, easy to understand and there is clear criteria that students can self-assess themselves against. The results are never communicated back to the school, are anonymous in every way and the responsibility for enrolling in the course resides with the student.
Another example can be found in the mathematics department of Athabasca University. Called the Mathematics Diagnostic Evaluation, it is an Authorware-based application that delivers three different difficulty categories of mathematics questions. Each question is multiple-choice, and some questions have visual aids such as figures and graphs, etc. Also, instead of guessing when the student doesn't know the answer they may simply click the skip icon. Like the text-based example at the Royal Military College, this test is simple to use (once you have Macromedia Authorware player installed on your machine). At the end of the test the program calculates a student's score and recommends which mathematics course they should begin with. Another strength of the test is that it then allows students to download all the correct answers if they are interested. One weakness I did notice was the lack of published criteria that students can self-assess themselves against. The algorithm of what score ranges result in what course recommendations would be nice to see. Again, like the text-based test discussed previously, the results in this test are never communicated back to the school, are anonymous in every way and the responsibility for enrolling in the course resides with the student.
In my view, although nothing replaces a useful academic counselling session with a real life body (whether face-to-face or on the phone), both of these tests are highly student-centered and can be valuable tools for the learner in planning their choice of courses at a distance.