Physics Learning at Large and Small Scales

How do we know how people learn physics? This is a fundamental question of measurement. Large N studies in Physics Education Research (PER) (~30k students) find correlates of student learning such as teaching methods, class sizes, and tests. Small N studies in PER (~30 students) investigate why students learn the way they do. Studies of both kinds are necessary to build a full picture of student learning in physics. In this talk, I discuss efforts to measure student learning using quantitive and qualitative data of physics students across the undergraduate curriculum and across institutions.