A learning indicator may qualitatively describe a learning process, or, more often, quantitatively summarize an important aspect of learning with a single or composite statistic. A qualitative indicator might take the form of a flow chart generated from a 'think aloud'from a student explaining why there is a change of season, or a categorization of students' explanations for why things sink and float. A quantitative indicator might be a measure of the change in a student's performance over time or an estimate of a college's value added to