Theory of Change

The ToC is a relatively new way of conducting evaluation research in the Netherlands and is steadily gaining ground. Risbo was one of the first organisations to apply this method successfully in a Dutch context, in collaboration with the Faculty of Social Sciences. Together they augmented this method with an effect measurement instrument.
The Theory of Change (ToC) approach to evaluation research stems from ideas by Carol Weiss (1972; 1995) and was elaborated further by others (Connell et al., 1995; Connell & Kubisch, 1998; Connell, Kubisch & Fulbright-Anderson, 2001). Weiss' starting point is that each intervention and each policy is based on specific assumptions about what the intervention will yield. Each intervention is intended to bring about a specific change. The ToC approach to evaluation research makes this explicit, and tests this explicit, or sometimes implicit, assumption. With 'Theory' Weiss did not specifically mean scientific theories, but the entirety of assumptions by professionals on the working mechanism of the intervention. So it concerns what has previously also been called a 'policy theory' or 'intervention theory'; an action theory as used in practice and by professionals (Hoogerwerf, 1984; Van Hoessel, Leeuw & Mevissen, 2005).
For three reasons the ToC approach constitutes a welcome augmentation to experimental or quasi-experimental evaluation research.
  1. The ToC evaluation encompasses more than simply measuring the effects of an intervention. With its focus on underlying assumptions on how an intervention works and how the intended effects are achieved, the ToC approach attempts to open the black box of interventions. After all it's not just about discovering whether specific objectives have been achieved or not, but also how that happens. In other words: what are the mechanisms through which an intervention arranges a specific effect?
  2. The ToC evaluation is close to actual practice. A ToC evaluation wants to launch a collective learning process among all those involved in a practical intervention. Weiss concluded that the ToC could be a good instrument to generate more knowledge about effective social interventions. If we really want to help families, children, youths etc., then we must understand the effects of complex interventions. The ToC offers the ability not only to perform good interventions, but mainly to gain an insight into how, when and why effective social interventions are performed.
  3. Finally, on the basis of the ToC approach, it can be said with reasonable certainty (but not with absolute certainty) that a causal link exists between the intervention and the observed effects. It is precisely the combination on the one hand of a plausible change theory which offers the ability to predict specific effects in advance, and on the other a thorough effect measurement, which shows that the predicted effects do actually appear.


Tom Tudjman
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3062 PA Rotterdam

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