, Volume 70, Issue 1, pp 213-216

First online:

A note on item information in any direction for the multidimensional three-parameter logistic model

  • Damon U. BryantAffiliated withUniversity Of Central FLorida At OrlandoDepartment of Psychology, University of Central Florida Email author 

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The purpose of this note is twofold: (a) to present the formula for the item information function (IIF) in any direction for the Multidimensional 3-Parameter Logistic (M3-PL) model and (b) to give the equation for the location of maximum item information (θ max) in the direction of the item discrimination vector. Several corollaries are given. Implications for future research are discussed.


item information measurement direction multidimensional measurement maximum information three-parameter logistic model