Main Article Content
Abstract
The original Guilford formula for estimation of multiple choice item difficulty was based on a penalty for guessing. This penalty was originally based on completely random or blind guessing, which means that it is purely based on mathematical estimation and on significantly violated assumptions. While authentic and fair estimation is expected to be based on mixed scoring formula which adds another correction factor to integrate measurement theory with decision theory based on partial knowledge and risk- taking behavior. A new formula with two correction factors related to guessing, partial knowledge and risk-taking is presented in this paper. Further studies are suggested for reviewing the validation of the main assumptions of item theory models.