This paper includes a nontechnical description of methods for calculating effect sizes in intellectual and developmental disability studies. Different hypothetical studies are used to illustrate how null hypothesis significance testing (NHST) and effect size findings can result in quite different outcomes and therefore conflicting results. Whereas…

This is a checklist of key items to get right when conducting a randomized controlled trial to evaluate an educational program or practice ("intervention"). It is intended as a practical resource for researchers and sponsors of research, describing items that are often critical to the success of a randomized controlled trial. A significant…