Study of the Model and Application for Estimated Difficulty
Liu B · Zhongguo kaoshi · 2009
Test score is mainly calculated by the items'difficulties,which affect the function of judgment and selection to the candidate directly.Difficulty,a very important to evaluate the item,is a fixed parameter after testing,when the cut-off score is deciding.The Estimated Difficulty,a model to estimate the item difficulty by test developers,is founded by constructing the Standard Norm Group of test takers,applied in the test developing process.The Model can keep the test stable and equity greatly by raw score.The Estimated Difficulty of item, can be conducted and adjusted in item editing,is different from the real data by statistical approach.The work in test developing is not only writing the items,but also designing and computing the Estimated Difficulty.