Latent structure
Three-Parameter Logistic IRT Model (3PL)
The three-parameter logistic (3PL) model, introduced by Allan Birnbaum in 1968, is an item response theory model that describes the probability of a correct response to a binary test item as a function of three item-level parameters — difficulty, discrimination, and a lower asymptote representing guessing — and one person-level parameter representing latent ability.
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Sources
- Birnbaum, A. (1968). Some latent trait models and their use in inferring an examinee's ability. In F. M. Lord & M. R. Novick (Eds.), Statistical theories of mental test scores (pp. 397–479). Addison-Wesley. link ↗
- Baker, F. B. & Kim, S. H. (2004). Item response theory: Parameter estimation techniques (2nd ed.). Marcel Dekker. ISBN: 978-0824758172