A multilevel meta-analysis of single-case and small-n research on interventions for reducing challenging behavior in persons with intellectual disabilities.

Griffith et al. (2012) pooled 285 single-case or small-n studies. The sample covered 598 people with intellectual disability. Every study tested an intervention meant to cut challenging behavior.

The team used multilevel meta-analysis. This let them compare effect sizes across different behaviors and procedures.

Interventions produced a large, significant drop in challenging behavior. The exact size of the effect changed with the type of behavior and the parts of the intervention used.

Results were positive overall, but the gains were not the same for every client or procedure.

Denis et al. (2011) looked only at self-injury and also found large reductions. Their 2011 meta-analysis is a close cousin to the current one, but it zoomed in on non-aversive reinforcement for profound ID.

Ogg-Groenendaal et al. (2014) narrowed the lens further. They reviewed only exercise studies and saw a 31% drop in challenging behavior. Their finding sits inside the broader 2012 pool, showing exercise is one workable tool among many.

Perry et al. (2024) took the next step. They coached 41 families to run function-based plans at home and 76% hit their goals. This extends the 2012 meta-analysis into real-world parent delivery.

The big picture is clear: most interventions work, but no single package fits all. Use the meta-results to pick strong components, then tailor to the client’s behavior type, sensory profile, and home context. Start with a solid functional assessment, add evidence-based pieces, and track data daily so you can adjust quickly.