After assessing the situation to determine the public health objectives and needs (see Assess the situation), the next step is to identify the type of intervention to implement.

Designing an intervention starts with establishing an inventory of existing initiatives in the field and distinguishing between elements that have or have not worked. Generally, this inventory is at least partially conducted during the assessment phase. It is preferable to prioritise interventions that have already been evaluated and shown to be effective. It is important to reflect on how these interventions can be adapted to cultural and local contexts.

 

Effective interventions: definition and relevance

An intervention is effective when it produces positive effects on the target populations in line with pre-defined objectives. The basis for the proof of its effectiveness is the establishment of a causal link between the intervention and the positive effects observed (e.g. smoking reduction, smoking cessation in part of the population of smokers).

Paying attention to the evidence of an intervention’s effectiveness has benefits throughout its life cycle: designing a project in relation to what works, proving that a project works, sustaining it if relevant or, on the contrary, putting an end to an unnecessary or harmful action.

 

Where to find information on the effectiveness of existing interventions?

• It is possible to conduct a rapid literature review of the interventions already implemented regarding a specific topic. Search tools and databases exist to facilitate such reviews: these are often document resources accessible online (e.g. the Cochrane Library gives access to literature reviews).
• Different intervention registries exist, which can help decision-makers and local actors to choose appropriate interventions for their needs, to implement scientifically based prevention. Registries evaluate the level of effectiveness of interventions using a precise and transparent methodology. For more information on registries, see the ‘Registries of prevention and health promotion interventions’ page. The Knowledge Hub website contains a catalogue of public awareness interventions focused on smoking prevention: unlike a registry, no methodology for classifying interventions according to their effectiveness has been established by the Knowledge Hub. The sole purpose of this catalogue is to list the interventions related to smoking prevention that are contained in the registries identified by the Hub.

Why prioritise previously evaluated and effective interventions?

• To save time on design 
• To save time and resources for evaluation 
• To gain experience 
• To capitalise on the initial notoriety, to gain scientific credibility (scientific publications) 
• To capitalise on time already invested (some interventions have been followed up for several decades) 
• Ease: to benefit from existing manuals, existing trainers and trainings, or pre-designed quality control systems 
• To focus on adapting to cultural and local contexts and evaluating adaptations, which may already represent a lot of work
• To focus on monitoring quality

Don’t forget: While reviewing existing interventions, remain alert to possible adverse effects that could occur in the local/intended context

 

If an effective intervention is identified, two options are possible:

1. The identified intervention is validated in a context comparable to the context in which it is intended to act . The implementation, follow-up and monitoring then take place in conjunction with the national or regional designer/developer of the project, as far as possible.
2. The intervention is scientifically validated but in a different context. All intervention materials, follow-up indicators and training programmes must be translated for and/or possibly adapted to the new context, without modifying the elements that make it effective. The evaluation should be discussed with the project designers. Depending on the case, a new efficacy evaluation in the new setting may be necessary.

 

 

What to do if no effective intervention has been identified?

Look for promising national or international interventions that have been the subject of an initial evaluation (quasi-experimental study or at least process evaluation). These interventions can be found via a scientific literature research or other existing search tools (such as specific registries). Once an intervention has been found that matches the objectives set, it will need to be adapted and, ideally, evaluated.

In the case of an identified intervention with no known impact, various questions should be asked:

• Has the intervention already been described? Does it have a convincing mechanism and logic of action?
• Is it possible to draw on previous experience and existing tools (guide, training documents, leaflets, etc.)?
• Does an evaluation suggest positive results, even if they have not been tested?
• Is there another intervention that meets the identified need with a higher level of evidence?

If these questions are answered negatively but there is still a wish to implement this intervention, it is possible to consider constructing a prevention research project, in collaboration with research teams, to measure the impact of the intervention. This choice involves a significant financial investment, as well as time and human resources.

However, it is important to construct the choice of the intervention with the stakeholders and in particular the beneficiaries or representatives of the community concerned; the various actors must be able to take ownership of the project in order to ensure its relevance and the adherence of the reference target.