Table 2.
Influences on what happens to an intervention following a null or negative effect trial
| Factor | Continued or future delivery of the intervention in its current form is more likely | Continued or future delivery of the intervention in its current form is less likely |
|---|---|---|
| The intervention | ||
| Stage of gestation | Intervention is mature and widely commissioned | Intervention is new or early in its development |
| Perceived importance | Well established and politically important | Lower profile and limited political importance |
| Implementation feasibility/acceptability | Easy to deliver well, liked by practitioners/users | Hard to deliver well, disliked by practitioners/users |
| Outcome(s) targeted | Considered important (is a potential threat to health) | Considered less important (not a threat to health) |
| Trial design, conduct, and results | ||
| Quality of trial design and conduct | Concerns about quality undermine confidence in results | Judged to be high quality and reliable |
| Pattern of outcome results | Somewhat inconsistent or inconclusive | Consistent and conclusive null/negative results |
| Context in which trial was conducted | Deemed significantly different to new/current context | Deemed to be similar to new/current context |
| Insight into reasons for the result | Explained by methodological or delivery issues | No reason to doubt or explain away the result |
| Nature of the control condition | Intervention of interest (I) vs. similar intervention (C) | Modification (I) vs. original intervention (C) |
| Context for decision-making | ||
| Evidence base for intervention | Multiple other trials with positive effects | No other trials, or other evidence equivocal |
| Wider evidence base | Similar interventions not obviously superior | Similar interventions show positive effects |
| Policy and practice imperatives | Need to do something, and nothing clearly superior | Some discretion about acting, or superior alternatives |
| Political and economic situation | Limited resources, and “better” alternatives cost more | Resources allow more effective but costly alternativea |
| Perspectives and interests | ||
| Investment in the intervention | Strong psychological or financial investment | Weaker investment, permitting more detached stance |
| Outlook on evidence (particularly trials) | Skeptical about evidence-based practice and/or trials | Sympathetic towards evidence-based practice/trials |
aOnly applies to existing interventions, not those delivered solely in the context of a trial