Before embarking on item analysis for achievement/ability items, the designer should decide on whether the assessment is a norm-referenced tool (NRT) or criterion-referenced tool (CRT). Item analysis studies will differ for NRTs and CRTs in terms of criterion groups used, formulas for computing item statistics, and the interpretation of results. Item statistics should be reviewed along with the qualitative characteristics of the item. Items for NRTs should have moderate to high difficulty and positive discrimination indices. CRT items should have instructional sensitivity in suitable curricular contexts.

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