Why trials lose participants: A multitrial investigation of participants’ perspectives using the theoretical domains framework
Bibliographic record
Abstract
OBJECTIVES: To use the Theoretical Domains Framework (TDF) to identify barriers and enablers to participant retention in trials requiring questionnaire return and/or attendance at follow-up clinics. STUDY DESIGN AND SETTING: We invited participants (n = 607) from five pragmatic effectiveness trials, who missed at least one follow-up time point (by not returning a questionnaire and/or not attending a clinic visit), to take part in semistructured telephone interviews. The TDF informed both data collection and analysis. To establish what barriers and enablers most likely influence the target behavior the domain relevance threshold was set at >75% of participants mentioning the domain. RESULTS: Sixteen participants (out of 25 showing interest) were interviewed. Overall, seven theoretical domains were identified as both barriers and enablers to the target behaviors of attending clinic appointments and returning postal questionnaires. Barriers frequently reported in relation to both target behaviours stemmed from participants' knowledge, beliefs about their capabilities and the consequences of performing (or not performing) the behavior. Two domains were identified as salient for questionnaire return only: goals; and memory, attention and decision-making. Emotion was identified as relevant for clinic attendance only. CONCLUSION: This is the first study informed by behavioural science to explore trial participants' accounts of trial retention. Findings will serve as a guiding framework when designing trials to limit barriers and enhance enablers of retention within clinical trials.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.386 | 0.972 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.025 | 0.009 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.008 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.005 | 0.017 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; both teacher heads agree on what is shown here.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".