The Theory of Change methodology is generally used for the conceptual evaluation of programmes and policies. The Theory of Change is defined as “a specific and measurable description of a social change initiative that forms the basis for strategic planning, decision making and ongoing evaluation” (Retolaza, 2011[1]). Its structure is somewhat flexible, which makes it possible to understand the linkages between the different components of a programme and identify the causality of the effects of an intervention.
The methodology can be seen as a semi-structured map of change that links strategic actions to certain process outcomes desired in the immediate environment. For its elaboration, it is necessary to define some elements identified by the methodology as key.
1. Purpose: The overall change that an intervention aims to achieve. It is possible that the intervention may not address the entirety of the purpose, but it should contribute to it.
2. Causal chain: This is a way of conceptualising an intervention based on five components:
Needs: They explicitly state the deficiencies to be addressed, specifying the target population. The needs should be measurable and directly related to final outcomes.
Activities: Actions that need to be carried out to produce an intervention’s outputs.
Outputs: The results derived from the combination of activities and inputs, with emphasis on the delivered product or service.
Outcomes: The immediate changes that occur as a result of an intervention and precede the achievement of overall objectives. They are usually associated with changes in attitudes, knowledge, skills and/or behaviours.
Final results: The medium- or long-term changes an intervention aims to achieve. They should be measurable and directly respond to the identified needs.
3. Relation between components: Once the components are defined, they need to be linked. That is, different activities should be related to the defined outputs, and in turn, the outputs should be associated with outcomes, and these should be connected to the final results. This helps explain an intervention's causality and how different actions affect outcome variables.
4. Assumptions and risks: Assumptions are external conditions (not directly dependent on the intervention) necessary to fulfil the causal chain. Risks are negative and unplanned effects (or externalities) of an intervention.
