Microsoft has been using an "Adaptive" format for certain tests for several years. I created an adaptive version of my test
applet that got used in a lot of Exam Crams and Preps from Coriolis.
The basic idea is that it "homes in" on your skill level by changing the difficulty of questions. The way I set it up was to track skill level for each of the major classifications of questions so you might get hard questions on one area but easy ones on another.
The US Army supposedly pioneered this kind of testing since they administer so many.
Creating a test like that takes a lot of work (and statistics) because you have to expose the questions to a lot of subjects to quantify how difficult they are. If you answer several questions at the top level, the system decides you know your stuff very quickly so the tests are short. It can also decide quickly that you will never pass.
Bill
------------------
author of: