studies that seek to explore change over time by sampling different (but comparable) samples at the same point in time – for example testing students in different grades on the same material to look for general differences (cf. longitudinal studies)
Prof. Keith S. Taber's site
studies that seek to explore change over time by sampling different (but comparable) samples at the same point in time – for example testing students in different grades on the same material to look for general differences (cf. longitudinal studies)