Skip to main content

Table 1 Checklist for incentive scheme design

From: Designing and using incentives to support recruitment and retention in clinical trials: a scoping review and a checklist for design

Design aspect to considerEvidenceIssues to considerFuture research priorities
1. What are the current incentives and barriers operating in the system?• Must complement the existing incentives already operating in the setting, and work to overcome the current barriers
• Consideration of the current state of play in a field is a key step but is frequently overlooked and can be affected by availability of information
• What incentives are in the setting already?
• What are the main barriers to recruitment?
• Understanding current systems of incentives operating in trials
2. Who should incentives be directed towards?• Choice should depend on where the greatest barriers exist, where accountability for improvement lies, and where the greatest gains may be achieved for the available resource
• Whilst there is more evidence to support patient incentives, all options show some promise
• Where do the greatest barriers to recruitment/retention currently lie? With participants, recruiters, or both?
• If the barriers are with recruiters, do individuals have the ability to overcome these, or is a team effort required?
• Testing organisational and individual incentives for recruiters, and shared incentive schemes
3. What should be incentivised?• Incentives linked to processes generally found to be more effective than outcome-linked incentives, although this evidence is from settings other than trial recruitment and retention
• There must be evidence of a strong causal relationship between the incentivised process and the desired outcome if process-based incentives are to achieve the overall aim
• What is the desired outcome? Recruitment, retention, or both?
• Would linking incentives directly to this outcome transfer unfair risk onto participants or recruiters?
• What processes may lead to this outcome? Is there evidence of a strong causal relationship between processes and this outcome?
• What other outcomes are important? Will these be neglected if not incentivised?
• Testing the relative benefits of process and outcome incentives and of incentivising a single metric compared to a range of measures
4. What form of incentive should be offered?• The psychological effects of monetary incentives do not appear to crowd out the direct price effect
• Monetary incentives were found to be more effective than non-monetary incentives for participants
• Who is the incentive directed towards? What are they likely to value most or be motivated by?
• Is it possible to provide monetary incentives?
• What is the overall budget for incentive provision?
• Testing of the relative effectiveness of monetary compared to non-monetary incentives for recruiters
5. How large should the incentive be?• Larger incentives should be more effective
• Size of incentive needed will be very context dependent, increasing in situations that require more effort from participants or recruiters, or more risk
• Incentive size will determine the overall cost of the scheme
• How are agents currently reimbursed?
• How much effort is required from participants or recruiters?
• How large is the risk associated with trial involvement?
• What is the overall budget for incentive provision?
• Would an incentive of the chosen size raise concerns around coercion?
• Testing the cost-effectiveness of larger incentives, accounting for the overall impact on study timelines and costs
6. How should the inventive be structured?• Incentive structure is crucial in determining the total cost of the scheme
• Most effective structure will vary by the context, and the evidence in this area is sparse
• Evidence suggests there is no difference in effectiveness between guaranteed and lottery-based incentives for patient incentives
• Repeat arrangements with recruiters may warrant exploration of more complex incentive structures
• Who is the incentive directed towards?
• If directed towards recruiters, is this a one-off situation or are repeat arrangements likely?
• What is the overall budget for incentive provision?
• Is budget certainty required from the outset?
• Do agents face different barriers to recruitment and retention?
• Exploration of the effects of more complex incentive structures
7. When, and how often, should payments be made?• Immediate incentives are generally found to be more effective than those paid out in the future
• The time between the occurrence of the desired behaviour and the incentive should be minimised
• When can incentives be practically provided in the trial?
• Is it possible to provide multiple incentives over time?
• Testing the benefits of multiple incentives over time
8. What are the potential unintended consequences?• In addition to their impact on recruitment and retention, the introduction of incentives may also result in unintended consequences
• Incentives should be designed to minimise the opportunities for individuals to engage in undesirable behaviours, and potential unintended consequences should be monitored
• Is incentive provision likely to lead to undue inducement or coercion of participants?
• Can exclusion criteria be easily verified?
• Are recruiters likely to game the system?
• What impacts are incentives likely to have in the long run?
• How can opportunities for individuals to engage in undesirable behaviours be minimised?
• What monitoring could be put in place to ensure quality trial conduct?
• Evaluating the extent to which potential unintended consequences materialise in practice