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Table 1 Rationale for conducting a pilot/feasibility study

From: Important considerations for feasibility studies in physical activity research involving persons with multiple sclerosis: a scoping systematic review and case study

Metric and reason Example of feasibility objectives in the literature Summary of systematic review results Result of feasibility outcome in Project GEMS [33]
Process: assesses the feasibility of the processes that are key to the success of the main study Determine recruitment rates [23, 24] (e.g. response of participants to recruitment strategies, proportion of respondents who remain interested in study after information and screening) Recruitment via MS Societies in the prospective location, clinician referrals, and trial awareness (through posters and leaflets) [7, 41, 4446, 48, 52, 53, 55]
Rationale for non-recruitment: travel difficulty, time restrictions [37]
Overall recruitment rate, 52%
Successive recruitment via postal invitation, 25%; email invitation, 30%; and telephone invitation, 22%
Determine ease of randomisation [24] (e.g. willingness of participants to be randomised to the proposed treatment group(s) No examples Not assessed
Resources: assesses the time and resource problems that can occur during the main study Estimate retention of participants in the study [23, 24]a (e.g. number of participants completing all aspects of study, number and reason for attrition) All participants completed study [35, 37, 39, 41, 44, 47, 52]
Drop out reasons: the intervention [7, 38, 58]; changes in time commitments [35, 51, 58]; unable to travel [42, 45, 46]; MS relapse [52]; other medical issues [7, 43, 45, 58]; non-compliance with the study protocol [7]; and lost contact [35, 37, 45]
90% of all participants completed study
Drop out reasons: changes in time commitment and other medical issues
Demonstrate appropriate eligibility criteria [23, 24]a (e.g. are criteria too inclusive/exclusive) All participants met inclusion criteria [47, 55]
Exclusion reasons: participants were too active [35, 41]; too old [35]; recent relapse [35]; participation in another trial [35]; participation in formal rehabilitation [42]; non-MS diagnosis [35]; recent change in disease modifying therapy [35]; high fall history [41]; and cognitive deficits [41]
32% of interested parties did not meet inclusion criteria. Exclusion reasons; too active, low self-reported disability level
Estimate barriers/refusals to participation [23, 24]a (e.g. participant transportation problems) Barriers identified: unable to travel [45, 46]; a change in personal time commitments [35, 51, 58]; MS relapse [52]; and other medical issues [7, 43, 45, 58] 10% of interested parties chose not to participate; unable to commit time
  Demonstrate compliance with study protocol [23, 24]a (e.g. do participants adhere to correct dosage of intervention sessions) Recorded via attendance at intervention [35, 3740, 4247, 50, 52, 58]; participant self-completed activity diaries [35, 37, 4547] 75% of intervention participants were fully compliant with exercise sessions
Demonstrate participants reaction to data collection and outcome assessments [23, 24]a (e.g. participants understanding of data collection tools) Compliance problems identified: participants unable to complete walking tasks [57]; general difficulties with assessment procedures [37] Time to complete outcome questionnaires: baseline, 40 min; follow-up 48 min
Estimate access to/cost of equipment, space, personnel time [24] (e.g. total cost of intervention delivery) Cost identified: staff, equipment and facility overheads [54] Cost per intervention participant: US$121.18
Determine the suitability of the intervention in the proposed setting [24] (e.g. suitability of a home-based exercise programme) Recorded via participant and staff interviews [43, 49, 52] Feedback questionnaires and telephone interviews indicate intervention suitable
Determine clinician training needs and competence [24] (e.g. training in outcome assessment and/or intervention delivery) Recorded via reliability of assessor [44], Reported as staff training requirements described [42, 44, 55] Not assessed
Management: assesses potential human and data management problems Estimate research site capacity [24] (e.g. phone-line, database, clinic/research site capacity) Reported as staff time required for recruitment [49] Staff preparation and reporting time: 263 h across 4 staff members
Estimate equipment usage [23] (e.g. ease of availability, personnel time, establishment of backup plan if equipment unavailable/broken) Problems identified: equipment related data collection problems [51] Not assessed
Determine processing time for data collection [23, 24] (e.g. time to mail data collection materials, time to complete outcome assessment) Reported asa staff time required for equipment processing and preparation [51] Mail turn-around-time to receive outcome assessments: 3 weeks
Estimate data completeness [24] (e.g. missing data items, missing outcomes) No examples Missing data: 2.5% at baseline, 7.2% at follow-up
Estimate data entry [24] (e.g. erroneous data) No examples Staff time to enter and check data: 61 h
Determine software appropriateness for data [24] (e.g. capacity of software for data analysis) Requirement identified: multiple software types necessary [55] Not assessed
Estimate processes to ensure and/or audit treatment fidelity [24] (e.g. clinicians adherence to protocol) Reported as experienced staff providing feedback on intervention delivery to the intervention instructors [42] Not assessed
Scientific: assesses the safety, burden data collection and response to the study Estimate challenges perceived/experienced by study personnel [23] (e.g. skills required to use assessment protocol) Requirement for more time for participants to complete assessments [49] Not assessed
Determine data collection materials appropriateness [23] (e.g. user friendly for data collection personnel) No examples Participants commented the outcome assessments were burdensome
Demonstrate potential extraneous variables which may threaten the validity of the research [24] (e.g. participant’ prior knowledge of intervention content) No examples Not assessed
Determine the acceptability to participants of the intervention(s) [24] (e.g. participants view on intervention before/during/after) Refer to original publications for individual details of the most acceptable exercise intervention [35, 37, 56, 57] Positive written and verbal feedback from participants on the appropriateness of the intervention
Estimate data variability in controlled trials [23, 24] (e.g. statistical analysis performed to establish baseline differences between groups) No significant baseline differences [7, 41, 4549, 58] No significant baseline differences in demographic or clinical metrics
Estimate treatment effect [23] (e.g. effect of primary outcome—not recommended) Significant interaction—recommend primary outcome [37, 39, 45, 46, 52, 58]
No significant interaction—cannot recommend primary outcome [44, 48, 49]
Significant interaction—recommend primary outcome
Determine appropriateness of target group for intervention [24] (e.g. are participants receptive to change expected in intervention) Positive feedback from participants on the appropriateness of the intervention [56] Positive written and verbal feedback from participants on the appropriateness of the intervention
  1. aConsidered assessment of process in reference [24]