The ABCD Study has enrolled 11,878 students and their families from all over the country. It is critically important that the participants in this study reflect the U.S. population of boys and girls, including children of diverse races and ethnicities, education and income levels, and living environments. To accomplish this goal, we partnered with public, private, and charter elementary schools in the continental U.S..
We identified all of the schools within a reasonable travel distance from each research site and selected a subset of the schools for enrollment. As enrollment occurred over a two-year period, we staggered our contact to schools so not all schools were approached at the same time. The careful selection of schools ensures that all demographic groups are included in the study so that the results are relevant for everyone.