How important should be data to teachers and how they could use it?

“Data is important, but more important is the teacher’s interpretation – how validity they make interpretations that then led to them enhancing/changing their instruction so that students’ progress. If there is no progression either the data was wrong, or the interpretation was wrong.  I have argued we have over emphasised the ‘data’ and not spent enough on the ‘interpretation’.  If measurement people for example, provided more interpretative information from the data from assessments this would make a huge difference. When we ask “Know thy Impact” we use data from many sources to then make interpretations – from test scores, artifacts of student work and assignments, from talking with students, and from observing students as they are undertaking their lessons” (John Hattie, personal communication, August 19, 2018).