Table 2 Feasibility objectives and outcomes

1. Determine the feasibility of recruitment to a large-scale RCT

a. Aggregate data on potential participants within NHS services

b. Number of patients assessed for eligibility / consented / randomised

c. Number and proportion of potential participants identified through NHS services, Join Dementia Research and by self-referral who are eligible

d. Reasons for non-inclusion / non-eligibility

e. Monthly recruitment rate per site

f. Barriers and facilitators to recruitment (focus groups)

2. Refine the eligibility criteria for a future definitive RCT

a. Number of screening failures for eligibility, post-consent

b. Participant and facilitator report (focus groups)

3. Determine the acceptability to patients / clinicians of randomisation

a. Proportion of eligible patients that consent to randomisation

b. Reasons for non-consent

c. Participant and facilitator report (focus groups)

4. Determine the relevance and acceptability to patients / clinicians of the trial intervention

a. Premature discontinuation or non-attendance of treatment and reasons

b. Feedback from participants and site staff delivering the intervention

c. Participant and facilitator report (focus groups)

5. Determine the acceptability to patients / clinicians of the trial procedures

a. Proportion of approached NHS sites that agree to participate in the trial and reasons for non-participation

b. Proportion of eligible patients that consent to randomisation

c. Reasons for non-consent

d. Withdrawals and losses to follow-up and reasons

e. Feedback from participants and staff (focus groups)

6. Assess the ability of NHS sites to deliver the intervention

a. Measures of the feasibility of delivering the PRIDE intervention within NHS settings:

 i. Number / grade / experience of staff within the service

 ii. Staff turnover

 iii. Time to treatment initiation

b. Measures of the recruitment and retention of PRIDE facilitators during the study treatment period

c. Barriers to treatment delivery per protocol (focus groups)

7. Assess training and support needs for NHS staff delivering the intervention

a. Feedback on training delivered (focus groups)

b. Support offered / accepted (e.g. log of calls and emails to central support lines)

8. Evaluate treatment fidelity when delivered through NHS services

a. Measures of treatment fidelity including:

 i. Adherence to intervention manual

 ii. Uptake of activities

b. Feedback from participants and staff (focus groups)

9. Determine the services and interventions provided as usual care and evaluate methods for measuring this

a. Post-diagnostic care pathway

b. Services available

c. Uptake of services

10. Assess follow-up and outcome completion rates

a. Response rate to follow-up assessment

b. Questionnaire completion rates

c. Amount of missing questionnaire data at item and scale levels

11. Determine the relevance and acceptability of a range of clinical outcome measures and selection of the primary outcome for the main trial

a. Completion rates and reasons for non-completion / missing data

b. Estimates of clinically important differences, variance and sensitivity to change for the clinical outcome measures

c. Direct questions to participants regarding relevance of measures

12. Evaluate the utility and acceptability of resource use questionnaires for use in an economic evaluation alongside a future RCT

a. Completion rate and reasons for non-completion / missing data

13. Comparative micro-costing of PRIDE intervention and usual care

a. Staff time and resources for delivery of PRIDE intervention

b. Other service use

14. Estimate the sample size required for a definitive study

a. Primary outcome selection

b. Variability in the outcome

c. Withdrawals and losses to follow-up

15. Determine the resources required for a full trial

a. Sample size, recruitment rate (number of sites / recruitment period), staffing and resources (for recruitment, treatment and follow-up)