Table 3.

Interview topic guide for the caregiving dyad interviews

The interview will be structured on the following areas of interest	Sample questions
Introduction	Overall, could you share your experiences of being involved with our research?
Determining participant views of their intervention	First of all, can you talk me through what study treatment you received? (prompt—clarify what was JOINT SUPPORT and what was usual care/non-study intervention)
The approach and consent process and willingness to be randomised to either group	Can you talk me through how you got into the study? You were allocated to X group. What did that feel like? Could we have dealt with that differently?
The acceptability of the care (both groups)	Would you be happy to talk me through your treatment? As X’s carer, what was your impression of the care. For both of you, what was helpful and less helpful to your care?
Group-based JOINT SUPPORT programme and telephone booster calls (experimental group)	How far did you find the JOINT SUPPORT programme helpful—for both of you. Can you give specific examples? What didn’t work as well? Did you get the telephone calls from the trial team? Can you remember what you talked about? Can you give specific examples of what was helpful, and l helpful? Was there any advice that confused you or you weren't clear about?
What the strengths of the experimental intervention (perceived effectiveness)	What were the most helpful/good-bits of your JOINT SUPPORT intervention? What was good about it What didn’t you like about it?
What the weaknesses of the experimental intervention	What were the less helpful/worse bits of the JOINT SUPPORT intervention?
What modifications they may recommend to interventions received (standard care and experimental groups)	What could we improve? (prompt: What do you think is lacking?) How do you think we could better support you and your carer to support you with chronic pain?
The risk of intervention contamination between the groups	Did you talk to any other patients or caregivers while in hospital about the intervention? Was there any discussion between those who received it and did not receive it?
The ease and convenience of the data collection processes (baseline and 3 months) (all participants)	As you were part of a trial, we had to collect a lot of measurements. Can you talk me through what these were? How easy were they? How convenient were they? Overall, do you have any points to make about the testing?
Applicability of the methods and measures used	How did you manage with the questionnaires we gave you at the start of the study and at the end in the post? Were they easy to complete or do you remember them being a problem?