This study was pre-registered on Open Science Framework in the project https://osf.io/pba92 (Doodeman et al. 2020, August 27). The link to this registration is: Doodeman, T. W. M., Sterkenburg, P., & Schuengel, C. (2020, August 27). The Construct and Convergent Validity of the 'Attune & Stimulate' checklist for parents and caregivers of persons with severe intellectual disabilities. https://doi.org/10.17605/OSF.IO/PBA92.
Doodeman et al. (Thu,) studied this question.