Evidence map›Paper›PMID 37936228›Full record

Trial reportTrials2023

Conditional versus non-conditional incentives to maximise return of participant completed questionnaires in clinical trials: a cluster randomised study within a trial.

Johanna Cook, Jonathan A Cook, Emily Bongard, Carl Heneghan, Chris C Butler

Open access · goldAbstract readRandomized Controlled Trial
In one paragraph

Trial report in Trials, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed, 1 pooled it
0.5field-weighted citation impact, top 27% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed, 1 synthesis or guideline pooled it, 2 citations in OpenAlex.

  1. Pooled it
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors at 2 institutions in 1 country.

Johanna CookThe Nuffield Department of Primary Care Health Sciences, University of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, UK. johanna.cook@phc.ox.ac.uk.
Jonathan A CookCentre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK.ORCID http://orcid.org/0000-0002-4156-6989
Emily BongardThe Nuffield Department of Primary Care Health Sciences, University of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, UK.
Carl HeneghanThe Nuffield Department of Primary Care Health Sciences, University of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, UK.
Chris C ButlerThe Nuffield Department of Primary Care Health Sciences, University of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, UK.
University of Oxford · GBNuffield Orthopaedic Centre · GB

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundHigh participant retention enhances the validity of clinical trials. A monetary incentive can increase retention, but it is not known if when it is provided and if it is conditional matters. We aimed to determine whether there was a difference in the number of follow-up trial questionnaires returned when a monetary (gift voucher) incentive was given to participants at recruitment (non-conditional), compared to informing participants at recruitment that the incentive would be given only once their 14-day daily diary (questionnaire) had been returned (conditional).

methodA cluster randomised study within a trial embedded within the Antivirals for influenza-Like Illness, An rCt of Clinical and Cost effectiveness in primary CarE (ALIC

resultsOf the 42 randomised sites (21 for each intervention), only 28 recruited at least one participant with only 10 practice pairs recruiting participants at both constituent sites. Raw diaries return proportions were 0.58 (127/220) and 0.73 (91/125) for non-conditional and conditional incentive groups. Regression analysis adjusted for site pair showed no significant difference in returns, - 0.09, (95% CI, - 0.29, 0.10, p = 0.34); when weighted, there was still no clear difference: 0.15 (95% CI, - 0.02, 0.31, p = 0.07). There was no clear statistical evidence of a difference in time taken to return questionnaires, nor the proportion of pages completed, by the intervention group in the main analyses (all p > 0.05). The conditional incentive was approximately £23 cheaper per diary returned based upon observed data.

conclusionThere was no clear evidence of a statistically significant difference in the proportion of participant-completed diaries returned between conditional or non-conditional incentive groups. The time to questionnaire return and completeness of the returned questionnaires were similar in both groups. There was substantial statistical uncertainty in the findings. Some of the sensitivity analyses suggested that a meaningful benefit of a conditional incentive of a magnitude that would be meaningful was plausible. The conditional approach costs less in cash terms.

Indexed as

MotivationHumansSurveys and QuestionnairesConditional incentiveIncentivesNon-conditional incentiveParticipant completed questionnaireSWAT

Identifiers

PMID37936228
PMCPMC10629007
OpenAlexW4388460779

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.