Overview

This evidence review will combine two different evidence gap maps into one learning exercise on transformational change.

We will indirectly review the evidence on transformational change in two sectors where there has been demonstrable progress: in energy and in behavioural change in public health. The review will use causal evidence to assess how lessons about transformational change in these two sectors may inform broader climate change mitigation and adaptation investments. The evidence gap maps will inform the scope of a subsequent systematic review.

For the purpose of our review, we operationalize transformational change in the following manner:

• A large depth of change: Transformational change requires a sizeable change. For the purpose of this review, we measure depth as the effect size of an intervention on outcomes.  
• A large scale of change: Even with large effect size, and intervention only becomes an important contributor of transformational change if it is targeting many beneficiaries or covering a large geographical area.
• Sustained change: For a change to be transformational, it must persist over time.