In practice, IRT (2PL/3PL) and Total Score may not be consistent. In case that, for two examinees, say S1 and S2, there are
IRT ability (S1) > IRT ability (S2)
Total Score (S1) < Total Score (S2)
Which one we should use for examinees' reported score?
Here, Total Score is the number of those correctly-responded items (testing questions).