- It is about measuring people's ability
- It uses items of high internal consistency.
- Therefore, if a person scores low on one item, he/she should be score low on the total scores as well. Likewise, if I score higher on the item than you do, my ability would be dominant over your ability.
- In IRT terminology, DIF (Differential Item Functioning) refers to "a difference in the probability of endorsing an item for members of a reference group (e.g., US workers) and a focal group (e.g., Chinese workers) having the same standing on the latent attribute measured by a test." It is related to dominance approach.
Ideal-point approach (Thurstone, 1928)
- It is about measuring people's attitude
- Individuals will endorse an item to the degree that it reflects
- More neutral items should be included