Overextrapolation

When one extrapolates, one speculates beyond what is known to be true to what may be true about something. In order to do this, you need to “fill in the gaps” of what you actually know with speculations and informed guesses. For example, let's say that you studied for only 45 minutes before taking the first test in a communications course and were surprised when you received an A. You might extrapolate from this fact and predict that, if you keep studying in the same way for future tests in communications, you will continue to do well on these tests. Although this extrapolation may turn out to be wrong, it seems reasonable to conclude that the best method of studying would not change much from one test to the next.

On the other hand, you would be over-extrapolating if you concluded that you could study in the same way for tests in your organic chemistry course and receive A’s on them. There are too many differences between the two courses to allow you to say that what is true for one is likely to be true for the other.

(See overgeneralization)
(See induction)