When you take a test in this class, you get a score, such as 89 (good for you) or 65 (back to the books!). That test score consists of several elements, including the observed score (or what you actually get on the test, such as 89 or 65) and a true score (the typical score you would get if you took the same test an infinite number of times). We can’t directly measure true score (because we don’t have the time or energy to give someone the same test an infinite number of times), but we can estimate it.
