Which is true regarding the item characteristic curve, or "S" curve, in Item Response Theory (IRT)?
A) It assumes that as people's abilities increase, their probability of answering the item correctly decreases.
B) A tall "S" means that an item has difficulty discriminating across ability.
C) IRT and the S curve assist in writing items to target specific ranges of ability.
D) It is useful in predicting the Standard Error of the Estimate.

Question

Quizplus · Accepted Answer

The item characteristic curve, or "S" curve, in IRT is useful in assisting in writing items to target specific ranges of ability. This is because the curve shows the item's performance across levels of ability, allowing test developers to see where the item discriminates best and where it may need improvement. Option A is incorrect because the "S" curve assumes that as people's abilities increase, their probability of answering the item correctly increases. Option B is incorrect because a tall "S" curve means that an item has good discrimination across ability, not difficulty. Option D is incorrect because the "S" curve is not used for predicting the standard error of the estimate.

Which Is True Regarding the Item Characteristic Curve, or "S