United Nations
Environment Programme

Theory of Change

Theory of Change 

Using a theory-based approach to evaluations allows us to forefront the assumptions that underpin causal chains from inputs to outputs and through to outcomes, intermediate states and impact. UN Environment evaluations are structured around a project or programme’s Theory of Change to assess the causal logic of the intervention and determine whether all external factors affecting outcomes, impact, sustainability and up-scaling have been carefully considered.

The Theory of Change of an intervention depicts the causal pathways from outputs through outcomes via intermediate states towards impact. The Theory of Change further defines the external factors that influence change along the major pathways i.e. factors that affect whether one result can lead to the next. These contributing factors are called drivers and assumptions. This approach has the benefit of incorporating the intended logic of an intervention into its implementation context.

Common definitions used in UN Environment are:

  • Outputs: services and products delivered directly by the intervention e.g. guidance material, policy advice, a local pilot project;
  • Outcomes: changes in stakeholder capacity resulting from outputs e.g. increased awareness, improved knowledge or skills, positive attitudinal and motivational changes, institutional or policy changes, availability of financing;
  • Impact: long term changes in environmental benefits and human living conditions e.g. reduced human-caused global warming, conserved biodiversity, improved water quality;
  • Intermediate states: changes required in between project outcomes and impact, e.g. wide-scale adoption of improved natural resource management practices, country-wide shift towards renewable energy sources;
  • Drivers: external conditions necessary for project results to lead to next-level results, over which the project has a certain level of control e.g. strong support from other development partners in-country, public pressure on policy makers and;
  • Assumptions: external conditions necessary for project results to lead to next-level results, over which the project has no control e.g. turn-over of government officials, global financial situation, technological advances.

The Theory of Change is represented in the evaluation report both as a narrative and diagrammatically. Although its primary use is to support an evaluation of effectiveness, the Theory of Change can be used to gain deeper insight into a wide range of evaluation criteria, such as sustainability or the quality of project monitoring etc.

         Download guidance on creating a reconstructed Theory of Change here.

         Download samples of UN Environment Theory of Change here.

         Supplementary Theory of Change resource 


Likelihood of Impact Assessment

It is often not possible to measure actual impact of a project due to data and resource limitations, and the timing of the evaluation. To assess the likelihood of impact, UN Environment evaluations often rely on a theoretical approach based on the intervention’s Theory of Change called Likelihood of Impact Assessment.