Standard for Producing Evidence — Effectiveness of Interventions — Part 1: Specification

The aim of producing evidence of the effectiveness of interventions is to enable decisions to be informed by knowledge of what works. This requires decision makers to have access to evidence that establishes whether an intervention contributes, in a causal sense, to the achievement of particular outcomes. Consequently, the objectives of evidence produced in conformity with this standard are to increase the degree of certainty about whether an intervention is effective at achieving its intended outcomes, and to make that knowledge accessible to those who might use it. Establishing the effectiveness or otherwise of an intervention requires a careful approach, in part because correlation does not automatically imply causation: simply observing an outcome after an intervention is not sufficient to prove that the intervention caused the outcome. Furthermore, people receiving one intervention may also be in receipt of others, so approaches that robustly establish the effectiveness of an intervention need to be designed to detect the part of any outcomes that are attributable to the intervention being studied. Evidence of correlation (as might be produced by evidence at level 1 in this standard) may increase the degree of certainty about the effectiveness of the intervention from ‘unknown’ to ‘might be working’. Producing this type of evidence can often be a useful and relatively simple first step in understanding the potential effectiveness of an intervention. Evidence of a causal link (levels 2 and 3) can take that further, towards ‘reasonably confident this works (at least in this context)’. Open publishing of details of studies investigating the effectiveness of interventions, both before commencing a study and reporting its findings, increases the potential impact of the evidence. It can do this both by enhancing the credibility of evidence findings and by making them more accessible to more decision makers. This standard specifies a process that supports those producing evidence to do so in a way that is robust and transparent. The process also includes steps such as reviewing existing evidence to support decisions about what type of evidence it would be most suitable to produce. In doing so, it will increase the potential for decisions to be made based upon accurate and credible evidence of the effectiveness of interventions.