As President Obama advocates for a dramatic expansion of publicly funded preschool [1], there is growing debate about whether preschool pays off academically for kids, says Michael Alison Chandler [2] for the Washington Post. Most controversial is the so-called “fade-out” effect that has surfaced in research, showing that students who attend preschool begin kindergarten more prepared than control groups of students who did not, but they lose their edge on reading or math tests within the first few years as other children catch up…