Nearly every modern instructional planning model, differentiation approach, and personalized learning system incorporates some form of re-assessment. Yet there's scant research evidence that teachers use pre-assessment in ways that improve learning, according to Guskey and McTighe. To increase the likelihood that pre-assessment will be worth the time and effort, the authors look at its potential purposes and problems. They offer three major recommendations: (1) always consider why you are pre-assessing, what information you are intending to uncover, and what methods you will use to gather that information--and make these purposes and methods explicitly to students; (2) Always take action to improve instruction on the basis of pre-assessment results; and (3) Use pre-assessments judiciously--only when they will provide information you don't already have and can't predict.