The amount of study
that is avoided by a person can be expressed using the following equation.
T = Time Spent Avoiding Study
A = Study Avoidance factor of person doing the study.
D = Difficulty of test.
L = Time left before test.
Thus it can be seen that the closer you get to the actual test the more time you will spend avoiding studying and the less actual study you will do.
Also the harder the test is, the more time will be spent not studying for it. This is a bad thing to happen because it means the amount of time spent avoiding studying increased as the as the tests get harder and the time before them get shorter.