Developing Pretend Play in Autistic Children Using the Playboxes Joint Play Approach as Part of Ongoing Practice.

The study used a small sample of only seven children without a control group, so natural development or other factors cannot be ruled out as causes for the changes. Assessments were not always conducted by a practitioner independent of the intervention, which introduces potential bias. The Symbolic Play Test had a ceiling effect, meaning it could not accurately measure progress for children who were already performing at the top of the scale. Participants were selected from children already receiving professional support, so results may not apply to autistic children in different contexts.

Do not assume the large score increases on the Test of Pretend Play prove the intervention caused the improvement. Without a control group, these gains could reflect natural development, practice effects, or other concurrent support, and the small sample size means individual variation was high.