Supervisory training for teachers: multiple, long-term effects in an education program for adults with severe disabilities.

The authors trained teachers to supervise classroom assistants who worked with adults with severe disabilities.

Training had two parts: a short class on giving feedback, then on-the-job coaching where the teacher watched and corrected each assistant.

The team tracked how well assistants collected data and how well teachers themselves taught.

Assistant data sheets became far more accurate after their teacher started giving feedback.

Teachers also taught better themselves once they had to coach others.

All gains lasted at least 17 months with no extra booster sessions.

Slane et al. (2021) looked at 20 later studies and found the same pattern: when teachers get BST, they run interventions with high fidelity.

Nishimura et al. (1987) did something almost identical eleven years earlier. They gave brief training plus principal feedback across 21 classrooms and saw two-year gains, showing the idea holds up across time and scale.

Johnson et al. (1994) trimmed the package even further. A simple weekly supervisor checklist lifted staff performance for four months, proving you don’t need fancy graphs to get durable change.

You can duplicate this tomorrow. Give your lead staff a 30-minute talk on clear, immediate feedback. Then have them watch and praise correct data collection on the spot. The 1998 study shows one round of coaching keeps accuracy high for over a year, and five other papers say the same. Start with your most error-prone assistant and let the cascade begin.