Classical Test Theory Stays True

Whether you call it "Classical Test Theory" or "True Score Theory", one thing can be agreed on and that is its importance. This theory takes into consideration the random error that can be involved and equated along with the "true ability" of the test taker. According to the Research Methods Knowledge Base website, the classical test theory is a power model for measurement. It takes into account the error component that most measurements have. The equation of Observed Score = True Ability + Random Error is about as reliable as it gets. This is due to the fact that "a measure that has no random error is perfectly reliable...a measure that has not true score has zero reliability". This relates exactly to the reliability theory. Apparently there is research being done to find out simpler ways to test all this out but it does not get simpler than this. This theory takes into account the true ability of the test taker and includes the random error that can be involved as one big concept.