Programme evaluation research centres around assessing the value, efficacy, and responsiveness of social and developmental programmes[1]. While there is no single correct way to define or conduct an evaluation, evaluative approaches are underpinned by a range of different social development theories. In practice, evaluators select a set of assumptions and methods that are appropriate to the programme context and purpose of the evaluation. It is however important to recognize that these assumptions and methods are underpinned by broader ideological paradigms, of which the three most common are described below.

The first paradigm is that of positivism, a philosophical theory asserting that factual knowledge can only be gained through the quantifiable observation and measurement of reality. Reason, logic, and scientific verification are central to the development of knowledge in positivism.[2] It assumes that reality is relatively independent of context and that it can be studied using objective techniques, such as standardized quantitative measures. When applied to evaluation, positivist approaches are concerned with the aspects of programmes that are systematically and objectively observable and measurable. Positivist evaluation methods are typically concerned with hypothesis testing using quantitative research methods, experimentation, and counterfactual testing to generate objective evidence in a systematic way. One of the key critiques of this approach is its narrow focus and unsuitability for research used in programme development.[3]

In contrast, the interpretive paradigm sees reality not as singular or objective, but rather as being shaped by human experience and social context. Evaluators working within an interpretive paradigm view programmes as being inherently embedded within a social setting, and place emphasis on understanding the values underpinning a programme[4]. While positivist evaluation approaches value the ‘outsider’ perspective of the evaluator, interpretive evaluative approaches rely on the personal and prolonged involvement of evaluators in programmes, without which they cannot understand how people create meaning in natural settings. Interpretive evaluation methods typically involve ethnography, qualitative interviewing, case studies, and beneficiary observations. A key critique of this approach its lack of reliability and scientific rigour given the reliance upon interpretation, consultation, and negotiation[5].

Finally, the critical emancipatory paradigm differs from both positivism and interpretive approaches in its concern with the agenda and interests of those involved in research. Evaluative approaches underpinned by critical social science are based on activist assumptions about knowledge and human interests, where research is seen as an operation of broader social forces that reinforce the existing social status quo and power relations in society[6]. The role of the evaluator is that of a change agent, who conducts research to transform social relations by critically analysing underlying forces that keep oppressive relations in place, and empowering programme stakeholders to identify and deal with their problems. Such evaluations focus on optimizing the educational value of evaluation to enhance the power, skills, and knowledge of the people involved in a programme. Evaluators play a facilitative, collaborative, and advocacy role and usually employ methods that engage programme beneficiaries in critical reflection and programme development using action research[7]. A key critique of this approach is its overt criticism of the scientific method as a tool used for the oppression of marginalized groups.

While there is no one correct way to design and conduct programme evaluations, it is important for evaluators to understand that the specific methods or techniques that they use in practice are informed by these different theoretical paradigms. Likewise, it is important to consider the relative merits and shortcomings of these different approaches in different settings. Ultimately, it is the job of the evaluator to select the paradigm and research methodology that is most appropriate to the programme being evaluated, the context in which the programme takes place, and the needs of the client.