Table 6.
Most popular retention strategies compared against evidence for effectiveness
| Top 10 most popular retention strategies in the scoping reviewa | Evidence from the Cochrane Review [1] to support the use of the strategies found in the scoping review |
|---|---|
| Reminders (n = 39, 14.7%) |
Reminders Evidence to support the use of various types of reminders is very uncertain and may result in little or no difference to retention rates, the GRADE of evidence for such reminders is either low or very low. Only telephone reminders compared to postal reminders may result in a large increase in retention rates; however, the GRADE of evidence is low. |
| Monetary incentives (conditional) (n = 27, 10.2%) |
Monetary incentives Monetary incentives compared to no incentive may increase retention but the GRADE of evidence is low. The addition of monetary incentives in all trial arms may favour the higher value incentive to increase retention but the GRADE of evidence is low. |
| Addition of a monetary reward to both trial arms delivered either with the prenotification or with the reminder letter, probably leads to an increase in retention rates, the GRADE of evidence is moderate. | |
| Evidence regarding the use of other types of monetary incentives are very uncertain and may lead to little or no difference in retention rates, with the GRADE of evidence being low or very low. | |
| Prompts (n = 17, 6.4%) |
Prompts Evidence to support the use of prompts is very uncertain and may lead to little or no difference in terms of retention rates, GRADE of evidence is low or very low. |
| Only prenotification cards vs no card and electronic prompts compared to electronic reminders looks to favour electronic reminders at increasing retention rates; however, the GRADE of evidence for both of these methods is low. | |
| Personalised prompts versus usual follow-up may reduce retention rates slightly but again the GRADE of evidence is low. | |
| Maintaining participant engagement (n = 14, 5.3%) | The evidence to support the use of various strategies to maintain participant engagement with the hopes of improving retention is very uncertain and may lead to little or no improvement in retention rates, the GRADE of evidence is low or very low for these strategies. |
| Including a newspaper article about the trial compared to no article may increase retention, similarly frequency of telephone contact comparing only at baseline to annual contact to contact only at baseline may increase retention but the GRADE of evidence for both strategies is low. | |
| Data collection location and method (n = 12, 4.5%) | Evidence is very uncertain and may lead to little or no difference in retention regarding postal vs clinic follow-up and regarding telephone follow-up vs postal follow-up, evidence GRADE is very low. |
| The use of first-class postage for outward mail versus second class postage may increase retention slightly, but the GRADE of evidence is low. | |
| Using free post versus second class stamp; high-priority mail stamp versus usual postage; and personal form all compared to usual postage practice for return postage may increase retention slightly but again the GRADE of evidence is low. | |
| The use of self-sampling kits (directly mailed or an invitation to order) probably increase retention, the GRADE of evidence is moderate. | |
| Supporting participation (n = 7, 2.6%) | No evidence from the Cochrane review |
| Data collection during routine care (n = 4, 1.5%) | No evidence from the Cochrane review |
| Non-monetary incentives (unconditional) (n = 4, 1.5%) | Including a pen compared to no pen may increase retention slightly but the GRADE of evidence is low. |
| The inclusion of a societal benefit messaged compared to usual follow-up may lead to little or no difference in retention rates, however the GRADE of evidence is low. | |
| The evidence to support the use of providing a certificate of appreciation compared to no certificate is very uncertain, and the GRADE of evidence is very low. | |
| Contact information (n = 3, 1.1%) | No evidence from the Cochrane review |
| Non-monetary incentives – (conditional) (n = 3, 1.1%) | See above for evidence for non-monetary incentives |
aAlthough the most common retention strategy in the review were the use of “combined strategies” used, we did not include this in the table as combined methods were not evaluated in the Cochrane Review [1]