Table 6.

Item optimization

Items modified following cognitive debriefing interviews (N = 18 caregivers)
Item/sub-domain	Rationale for modification following set 1 (n = 9)	Rationale for modification following set 2 (n = 9)
Physical effort	Item wording changed from ‘how much physical effort has it taken you to do caregiving tasks’ to ‘how much has caregiving been physically hard work?’ to improve clarity and understanding to caregivers.	No further modifications
Body ache	3/9 caregivers thought about pain as well as aches so item changed to ‘During the past 4 weeks, how much has caregiving caused you physical aches and pains?’	The term ‘physical’ was removed as caregivers felt it was redundant. Final item wording: ‘how much has caregiving caused you aches and pains?’
Feeling overly depended upon	Item revised to use a frequency scale rather than an intensity scale to fit better with the item wording. Revised item wording: ‘how much of the time have you felt you need to do more for the person you care for?’	More than half of the caregivers preferred to omit the new wording how much of the time’. Item returned to original wording: ‘how much have you felt like you need to do more for the person you care for?’
Difficulty concentrating/focusing	The term ‘focus’ was included alongside ‘concentrate’ to improve clarity and interpretation. Revised item wording: ‘how much has caregiving made it difficult to focus or concentrate on other things?’	Including ‘focus’ alongside ‘concentrate’ appeared to help most caregivers interpret the item correctly. No further item modifications.
Lack of time for self	To be consistent with the negative phrasing of the other items and to avoid confusion, the item was changed from ‘how much have you felt like you have had enough time for yourself?’ to ‘how much have you felt like you have no time for yourself?’	No further item modifications.
Time spent with family and partner time spent with friends	Two separate items were tested for these two sub-domains and feedback demonstrated that caregivers found both items easy to understand and relevant.	In the final item the two separate items were merged to reduce the number of items overall. Final item wording: ‘how much has caregiving limited the time you spent with partner, family or friends?’