7.6 Steps for conducting a reverse logic analysis

Reverse logic analysis involves similar but slightly different steps. The objective is to identify different alternatives for achieving desired results. Reverse logic analysis is particularly useful when no intervention preexists, but it could be used when an intervention already exists to broaden the range of possible actions to achieve specific results. It provides valuable information on how to design effective interventions to achieve specific, predetermined effects. Before starting, the different parties involved in the evaluation should agree on the expected results they are trying to achieve with the intervention. Reverse logic analysis uses 2 steps.

Step 1: Identifying different alternatives

By consulting experts and conducting a search of the scientific literature, the evaluator will identify one or more interventions—or alternative approaches—that could lead to the expected effects. The intervention(s) will be the result of synthesizing various writings, while considering the context and its influence on the production of effects. If the existing body of knowledge suggests multiple alternatives that cannot be combined, distinct interventions could be identified, followed by a deliberative process to select the intervention most appropriate for the implementation context. The goal is to identify, based on scientific and expert knowledge, one or a small number of interventions that will lead to the desired results. All effects documented in the literature review should be incorporated into the interventions’ theory of change, as some interventions may also lead to undesirable effects.

As the objective of this type of evaluation is to provide evidence-informed knowledge to help make the best decision possible on what kind of intervention to implement, all relevant information should be included. This also involves documenting the potential impacts on natural and human systems. As mentioned above, these impacts will depend on the context of implementation. Even if discussions are needed with the implementers at a later stage, it is the role of the evaluator to identify the areas of environmental and social impacts at this stage; this step can be completed based on the evaluator’s own knowledge or by consulting relevant experts.

In summary, the role of the evaluator will be, first, to synthesize the information available from the scientific literature and related to impacts on planetary health. This step may lead to the formulation of one or more theories of change identifying the mechanisms and the contextual conditions by which the intervention will generate effects, as well as the full spectrum of anticipated outcomes, including those affecting environmental and human systems.

Step 2: Selecting the most promising intervention

The second step involves organizing a deliberative activity with the actors in the field to identify the most relevant intervention according to the implementation context (Tremblay et al., 2013). This step involves identifying the range of possibilities and mechanisms of action based on expert and scientific knowledge, and then integrating these insights with the specific characteristics of the implementation context. The choice of intervention will depend on the contextual characteristics (Rey et al., 2012). The deliberative approach should include discussions about alternative interventions and their potential impacts on planetary health, followed by strategies to explore ways to revise the theory of change in order to shift from negative impacts to positive outcomes.