Development of a scale to measure fidelity to manualized group-based cognitive behavioural interventions for people with intellectual disabilities.

Jahoda et al. (2013) built a 30-item checklist called the MAGIC scale. It tracks how closely staff run group CBT for adults with intellectual disability.

Two raters watched the same sessions and scored items like "used simple words" and "checked mood." The team then tested if high scores matched better client anger control.

Raters agreed strongly on each item. Higher fidelity scores predicted bigger drops in anger outbursts after the group ended.

In short, when staff followed the manual, clients got better.

Eussen et al. (2016) reviewed every trial they could find on mental-health care for adults with mild ID. They saw only weak proof for any method, yet group CBT had the best signal. The MAGIC scale gives teams a tool to protect that fragile signal by keeping quality high.

Goodwin et al. (2012) listed many ID mood scales but none for fidelity. MAGIC fills that gap, so researchers can now link process to outcome.

Reiss et al. (1993) built a scale for psychiatrist interview skills. Like MAGIC, it showed raters can reliably score subtle clinician behaviors on video, proving the method travels across decades and roles.

You now have a free, 30-item scale that takes 10 minutes to complete. Use it after you film any group CBT session. Share the scores with staff the same day, praise the steps they hit, and retrain the ones they missed. This quick loop keeps your anger-management groups sharp and outcomes strong.