Does Treatment Fidelity of the Early Start Denver Model Impact Skill Acquisition in Young Children with Autism?

Zitter et al. (2023) watched therapists run Early Start Denver Model sessions with toddlers who have autism.

They scored each therapist on the ESDM checklist while the child worked. Then they counted how many new skills the child showed in that same hour.

When the checklist score was high, the child learned more targets right inside the session.

Lower scores meant fewer learning moments, even with the same lesson plan.

Halbur et al. (2024) also saw higher fidelity after giving teachers smarter data sheets. Both papers say the same thing: small tools that remind you what to do lift your teaching quality.

Yanchik et al. (2024) blended NET with DTT and got bigger adaptive-skill jumps than DTT alone. Ashley’s work adds the why: the blend only helps when you run it with high fidelity.

Pitts et al. (2021) pushed for 100% mastery criteria while Lloyd et al. (2021) warned that one error-fix tactic does not fit all kids. Ashley’s data say the first step is simply doing the protocol as written; without that, mastery rules or clever prompts may not matter.

You can have the best ESDM manual on the shelf, but the child only gains when you hit every bullet on the checklist. Start each session with a quick self-rate: if you skipped a step, stop and add it before moving on. That tiny pause can turn a flat lesson into a burst of new skills.