Logic models are part of a wider family of evaluation approaches that seek to describe programme theory. Other members of this family are 'theory of change' and realistic evaluation. Chen (1990) describes programme theory as "a specification of what must be done to achieve the desired goals, what other important impacts may also be anticipated, and how these goals and impacts would be generated". Chen makes the distinction between two phases in programme theory; 1) normative theory, which provides the rationale and justification for the programme structure and activities, and 2) causative theory, which represents the empirical knowledge about the causal relationship between the intervention and the outcome.
These two phases are reflected in logic models which describe the activities that are thought to bring about change, and links these activities to the results the programme is expected to achieve. Results are generally described in terms of outputs, outcomes and impact. Owen (1999) notes that central to the notion of logic models is the idea of programme causality, the ordering of events in such a way that the presence of one event or action leads to, or causes, a subsequent event or action. While this implies a linearity that is inconsistent with the complexities of programme design and implementation, causal thinking is the basis for programme planning, without which there would be no basis for developing interventions.
In the application of this technique the evaluator follows the opposite logic that the designers do in the design of a programme. Planning and evaluation are two sides of the same coin; the causal chain of the problems and causes is the negative image of the causal chain of objectives and instruments. The evaluator role is to establish the gaps in the causality chain in order to improve the programme.
Logical framework is based on logic models and provides a practical tool for the analysis, design, management, and refinement of programmes. The following chapter provides an introduction to the logical framework approach and technique.
Logical framework
The logical framework technique is an exercise in structuring the component elements of a project (or single programme) and analysing the internal and external coherence of the project. The product of this technique, the logical framework, is a formal matrix presentation of the internal functioning of the project, of the means for verifying the achievement of the goal, and of the internal and external factors conditioning its success. An example of the approach is given in Box Logical framework of a local fishing project