PSY 370 Lecture Notes - Lecture 19: Psychometrics, Psy
Document Summary
We want to be able to estimate where people fall along the continuum of our construct. So we need items that vary in difficulty to tap different levels of the construct. "how far along the continuum are people who endorse this item?" *this has nothing to do with cognitive effort. *how much of the construct do you need before you endorse an item. It"s sort of like how much exposure you"ve had to the construct before. The question "what"s 2+5" would not be a question of pretty high difficulty, but would indicate what point on the continuum (cutoff) you rank at. Difficulty = % of people who got the item right. ***the % of people that got the item right is also the mean! Item "difficulty" when there"s no right answer (non-dichotomous items) "difficulty" is not really the best term--some use "endorsement" Has nothing to do with the item being confusing.
