Full Question: How do you place a numerical value on data that you collect that is qualitative? Using metacognition for example, how do I measure its effect when I wouldn't generally have an assessment that provides a numerical value to calculate? What am I looking at? Is it key words in a survey and then scoring them or something along those lines? Or, is it still through content areas and you create samples where some are focused on metacognition in maths and some are not? Does calculating effect sizes work when you are trying to develop more than one thing in a classroom at a time or does it make it difficult to pinpoint the actions that are having the greatest impact?
Answer: “Effect sizes are but one, although powerful, tool in the toolbox. It should be used as part of triangulating other sources (teacher judgment, qualitative judgments about student artifacts, and student voice). I would worry about an over dependence of effect size but certainly advocate their use as a core part of the evaluation of our impact. I do argue that most of what we do in schools can be converted to a quantitative scale and there is now a 100-year history of psychometric research about how to do this--and sometimes the energy and knowledge to do this outdoes the value of the conversion. Yes, we can develop learning progressions in many attributes, scoring rubrics related to this, and then moderate student responses to these--and thence can use effect sizes, especially more evaluating change over time” (John Hattie, personal communication, April 17, 2019).