They compared the progress of young children on the autism spectrum who received 25–40 h a week of one-to-one applied behavior analysis (ABA) with a comparison group who experienced an eclectic approach mixing several different techniques and a mix of teaching ratios including some one-to-one, and some one-to-two for 30 h a week. The children who got 25–40 h a week of ABA had a better outcome than the children who had eclectic instruction. Thus hours in the classroom are not helpful if they do not provide intensity of instruction in a data-based approach to treatment.