STAGE 6. Defining the evaluation plan

What steps should be completed?

Step 1: Select the type of evaluation



Outcome evaluation1 is the procedure that allows the effects of an intervention to be determined. It illustrates the extent to which the objectives have been achieved and aims to ascertain whether the changes in the population (or in its environment) are occurring as they have been formulated in the objectives. The outcome evaluation has two purposes:

  1. To assess whether the intervention is effective and, therefore, if it serves to achieve the results.
  2. To validate the intervention, or discard it if it is no use for its designed purpose or if it has a counterproductive effect on the population.

While the process evaluation is accessible by any professional designing and developing an intervention, the requirements for an outcome evaluation are more demanding. Assessing the efficacy of an intervention requires a high level of technical knowledge, experience of evaluation and more financial and time resources.

The results of any intervention can be evaluated, but this is more necessary in some interventions than others so, when designing an intervention that includes elements that have not been researched or about which there is not enough evidence, it is highly advisable to carry out an outcome evaluation to discover the efficacy of the intervention. However, it is possible not to evaluate the results (especially when resources are scarce) in interventions that are widely implemented, which have been implemented and assessed in advance and which are known for their efficacy and effectiveness. In these cases, if the actions are implemented with guaranteed accuracy with respect to the original programme or intervention, making the cultural changes necessary for the population to accept them without affecting key components, it is reasonable to assume that the current intervention will produce results equivalent to those achieved by the original interventions.

The main technical concerns that arise when planning an outcome evaluation are: a) to determine to what extent the changes observed can be attributed to the intervention, and b) to assess to what extent the results achieved with by intervention can be extrapolated to the rest of the population that shares similar characteristics with the target population.

The type of outcome evaluation design used is crucial to clarify previous doubts and determine the potential for explanation of the results of an intervention. +



1 Adapted from Alonso C, Salvador T, Suelves JM, et al. (2004). Prevención de la A a la Z. Glosario sobre prevención del abuso de drogas [Prevention from A to Z. A drug abuse prevention glossary]. Madrid: Centro de Estudios sobre Promoción de la Salud.