Table 4 Delphi survey research priorities for assessing the effectiveness of missing data interventions
From: Identifying research priorities for effective retention strategies in clinical trials
Scores | Round 1 | Round 2 | Ranking | ||||
|---|---|---|---|---|---|---|---|
Missing data intervention | %1–3 | %4–6 | %7–9 | %1–3 | %4–6 | %7–9 | |
Site initiation training on missing dataa | 6% | 19% | 75% | 6% | 11% | 83% | 1 |
Frequency of patient contact during the triala | 3% | 31% | 66% | 0% | 21% | 79% | 2 |
Use of routinely collected dataa | 6% | 22% | 72% | 6% | 17% | 77% | 3 |
Frequency and timing of remindersa | 0% | 34% | 66% | 0% | 24% | 76% | 4 |
Triggered site training on missing dataa | 6% | 31% | 64% | 3% | 23% | 74% | 5 |
Length/time needed to complete the questionnairea | 11% | 28% | 61% | 9% | 17% | 74% | 6 |
Frequency of contact between central trial staff and investigators | 11% | 31% | 58% | 6% | 26% | 69% | 7 |
Impact of site recruitment rates on data collection | 9% | 31% | 60% | 9% | 23% | 69% | 8 |
Postal or online questionnaires | 3% | 39% | 58% | 3% | 31% | 66% | 9 |
Frequency of questionnaires | 6% | 36% | 58% | 6% | 29% | 66% | 10 |
Data collection scheduled with routine care | 8% | 31% | 61% | 9% | 26% | 66% | 11 |
ONS flagging of patients | 15% | 27% | 58% | 16% | 19% | 66% | 12 |
Impact of local site researcher/clinical staff continuity | 6% | 34% | 60% | 3% | 32% | 65% | 13 |
Telephone reminders | 9% | 34% | 57% | 9% | 26% | 65% | 14 |
Contacting GPs for missing data or to trace patients | 17% | 31% | 51% | 9% | 26% | 65% | 14 |
Only collecting the primary outcome for patients with missing primary and secondary data | 6% | 32% | 62% | 6% | 30% | 64% | 16 |
Email reminders | 0% | 45% | 55% | 3% | 34% | 63% | 17 |
Patient data entry, e.g. use of mobile phone applications (apps), online data or other systems | 9% | 34% | 57% | 6% | 32% | 62% | 18 |
Staggered per patient payments based on patient progress and data collection | 9% | 29% | 63% | 9% | 29% | 62% | 19 |
A timeline reminder of participant visits for sites | 11% | 37% | 51% | 9% | 32% | 59% | 20 |
Flexibility in appointment times, e.g. data collection window | 6% | 42% | 53% | 6% | 37% | 57% | 21 |
Site selection strategies | 11% | 37% | 51% | 11% | 31% | 57% | 22 |
Questionnaires completed in the presence of researchers/clinical staff | 11% | 39% | 50% | 11% | 31% | 57% | 22 |
Case management, e.g. arranging appointments and helping patients access health care | 19% | 35% | 45% | 20% | 23% | 57% | 24 |
Re-imbursement of participant expenses | 11% | 37% | 51% | 6% | 38% | 56% | 25 |
Postal reminders | 11% | 40% | 49% | 9% | 35% | 56% | 26 |
Questionnaires returned to local sites vs central office, e.g. is monitoring of response rates and follow-up of missing questionnaires best performed by local sites or central trial offices | 9% | 37% | 54% | 9% | 35% | 56% | 26 |
Data collected by phoning the patient | 11% | 37% | 51% | 9% | 37% | 54% | 28 |
Inclusion of prepaid envelope | 22% | 36% | 42% | 23% | 26% | 51% | 29 |
SMS text reminders | 12% | 45% | 42% | 13% | 38% | 50% | 30 |
Teleconference meetings with investigators | 11% | 42% | 47% | 9% | 43% | 49% | 31 |
Clinician/researcher-collected outcomes versus PROMS (patient-reported outcome measures) | NA | NA | NA | 13% | 41% | 47% | 32 |
Location where questionnaires are completed, e.g. home or clinic | 8% | 42% | 50% | 9% | 46% | 46% | 33 |
Retention and withdrawal information within the Patient Information Sheets | 14% | 42% | 44% | 14% | 40% | 46% | 34 |
Follow-up through patient notes only | 14% | 43% | 43% | 9% | 47% | 44% | 35 |
Research nurse teleconferences or face-to-face meetings | NA | NA | NA | 3% | 54% | 43% | 36 |
Use of social media to contact participants | 13% | 47% | 41% | 10% | 48% | 42% | 37 |
Flexibility in appointment locations, e.g. home or clinic | 14% | 39% | 47% | 14% | 46% | 40% | 38 |
Site newsletters | 11% | 44% | 44% | 14% | 49% | 37% | 39 |
Availability of blinded outcome assessors to ensure data availability and quality | NA | NA | NA | 29% | 35% | 35% | 40 |
Routine site visits by CTU staff | 8% | 53% | 39% | 3% | 63% | 34% | 41 |
Timing of sending questionnaires, e.g. before or shortly after a visit | 11% | 51% | 37% | 9% | 57% | 34% | 42 |
Collecting multiple contact details for participants | 24% | 38% | 38% | 24% | 42% | 33% | 43 |
Face-to-face meetings with investigators | 6% | 58% | 36% | 6% | 63% | 31% | 44 |
Patient diaries to collect data | 11% | 50% | 39% | 14% | 54% | 31% | 45 |
Total Design Method (Dillman [31]), a specific approach to maximise questionnaire response rates that utilises cover letters, reminders and resending questionnaires | 16% | 44% | 41% | 16% | 53% | 31% | 46 |
Behavioural motivation strategies, e.g. workshop for patients to help facilitate completion of intervention and follow-up | 24% | 45% | 30% | 30% | 42% | 27% | 47 |
Format of newsletters and mode of delivery | NA | NA | NA | 12% | 62% | 26% | 48 |
Offer of trial results for participants | 11% | 58% | 31% | 11% | 63% | 26% | 49 |
Frequency of newsletters | 8% | 64% | 28% | 6% | 74% | 20% | 50 |
Question order, e.g. health-related, generic or medical questions first | 11% | 61% | 28% | 6% | 74% | 20% | 50 |
Patient newsletters | 16% | 59% | 25% | 13% | 68% | 19% | 52 |
Open trial design | 41% | 44% | 15% | 42% | 45% | 13% | 53 |
Timing of monetary/gift voucher for participants, e.g. given conditionally on completion of assessment or unconditionally at the beginning or end of trial | 29% | 47% | 24% | 27% | 61% | 12% | 54 |
Monetary incentives or gift voucher incentives for participants | 29% | 44% | 26% | 30% | 58% | 12% | 55 |
Transport to and from appointments | 14% | 63% | 23% | 15% | 76% | 9% | 56 |
Taking contact details for friends/family of participants | 31% | 50% | 19% | 32% | 61% | 6% | 57 |
Gift for participant | 42% | 45% | 13% | 42% | 52% | 6% | 58 |
Prize draw limited to trial participants | 41% | 44% | 16% | 34% | 59% | 6% | 59 |
Enhanced cover letter | 24% | 55% | 21% | 21% | 73% | 6% | 60 |
Trial certificate | 44% | 50% | 6% | 50% | 44% | 6% | 61 |
Trial website | 31% | 53% | 17% | 26% | 69% | 6% | 62 |
The use of a Freephone number for updating participant’s contact details | 35% | 58% | 6% | 40% | 57% | 3% | 63 |
Trial identity cards | 39% | 52% | 10% | 42% | 55% | 3% | 64 |
Use of social media to contact site staff | 33% | 55% | 12% | 38% | 59% | 3% | 65 |
Gift for site staff | 45% | 52% | 3% | 36% | 61% | 3% | 66 |
Christmas and/or birthday cards for participants | 48% | 45% | 6% | 64% | 33% | 3% | 67 |
Type of post used, e.g. priority, standard or recorded post | 34% | 54% | 11% | 29% | 68% | 3% | 68 |
Personal touch, e.g. handwritten letter or addition of post it notes | 26% | 71% | 3% | 27% | 73% | 0% | 69 |
Offer of a crèche service | 50% | 46% | 4% | 57% | 43% | 0% | 70 |
Christmas cards for site staffb | 67% | 33% | 0% | 82% | 18% | 0% | 71 |