Table 1

Sample strategy and characteristics

Phase	Participants	Sampling strategy	Sample size
1	Senior managers/LDLN	Senior managers from the trust identified by the local collaborator as having relevant knowledge of hospital services and provision. All staff with a defined role for CYP with ID.	36–54
1	Hospital staff	All clinical and non-clinical staff with contact with CYP and their families will be invited.	1800
2	CYP and parents	A purposive sampling strategy using a sampling matrix to ensure diversity according to level of ID, age, ethnicity.	56–64 CYP 56–128 Parents
	Hospital staff	All ward managers on each study ward will be invited. A purposive sample of hospital staff identified by parents or CYP as making a difference to their care.	12 ward managers 112–128 hospital staff
	Community staff	All community professionals named by parents as being involved in the care of their child.	280–320
3	CYP and parents	All CYP and parents discharged from participating wards.	60 CYP 360 Parents

CYP, children and young people; ID, intellectual disability; LDLN, learning disability liaison nurse.