In the past I have used a program call MyMathLab (or MathXL) to test students understanding of mathematical concepts. One of the frustrations I always had was that students could use a "help me solve this" or "view an example" help tool to walk them through their assignments, but they never learned. This resulted in very high homework scores, but not as good of scores on the exams. For example, in Spring 2011, my students had a class average of 93.8% on the homework and 88% on the quizzes. However, their midterm average was only 80.7% and the final exam average was only 70.7%.
In Fall 2012, I began using a new program called IMathAS, which does not have the same help tools. It is more instructor friendly in that it allows me to edit questions more easily. Students needed to score a 90% on a homework assignment or no credit was given and a 80% on quizzes or no credit was given. The students had an 84% average on homework and an 84% average on quizzes, but their exam averages increased to 86.9% on their first exam and 86.35% on their second exam. They also had an increase in Final Exam average to 81%!