As the three examples I’ve sketchily outlined here indicate, learning loss can’t be understood as a ‘whole’ without disaggregating it into its disparate elements and the various measurement practices they rely on. I’ve counted only three ways of measuring learning loss here—the original psychometric studies; testing companies’ assessments of reading and numeracy; and econometric calculations of ‘hysteresis effects’ in the economy—but even these are made of multiple parts, and are based on longer histories of measurement that are contested, incompatible with one another, sometimes contradictory, and incoherent when bundled together.
Ben Williamson explores what we talk about when we talk about learning lose. He discusses Barbara Heyns’ 1978 publication Summer Learning and the Effects of Schooling, data associated with NWEA MAP Growth test in the US, and recent large-scale studies of learning loss by organisations such as OECD and World Bank. What this all highlights is the complexities associated with the idea, as well as the various commercial and political influences.