Impact assessment

We usually talk about the impact of an object, projectile, force, action and its effect, footprint, signal or consequence on something or someone, but the impacts that concern us in today’s article are those that refer to public actions or In a socio-economic environment.

We can define the impacts of any action or intervention in a system as the set of changes (expected and unforeseen, positive / desired and negative / unwanted) produced in the different elements of the system and in the relationships between the elements because of that intervention.

Impact Assessments aim to measure, through the use of certain methodologies, the effects (outcomes, results, consequences, …) of an action, plan, program or project on the target population or population (beneficiary and the Population) and to know if these effects are actually attributable to such intervention (causality), their magnitude, and to what extent they were achieved in relation to what was expected. Impact assessment must take into account the medium and long term, otherwise, if only what is obtained just at the end of the action is collected, we will be talking about evaluation of results.

The main challenge of an impact assessment is to determine what would have happened to the beneficiaries if the program or intervention had not existed. This analysis is called Counterfactual Analysis (see bibliography at the end).

Changes or effects may relate to:

  • Economic factors
  • Technical factors
  • Social and cultural factors
  • Institutional factors
  • Environmental factors
  • Scope (Segments of affected target population, companies, individuals)
  • Measuring changes in the well-being of individuals

Impact assessment can be useful for transparency, accountability and verification of effectiveness, effectiveness and efficiency * in the use of resources, and therefore of their administration, control and decision-making (government) and Of its legitimacy. It is also the best way to learn and improve in future actions.

*Efficacy: Reaching the target theoretically

  Effectiveness: Achieve concrete and specific goal in practice

  Efficiency: Achieve the concrete objective in practice with the lowest possible cost

The questions that can be asked for an impact assessment are multiple:

  • Are we doing the right things?
  • Are we doing things properly?
  • How can we do things better?

In short, the actions performed  – Do they work or not? Where? Why? To what extent? What evidence do we have?

The process for responding (a posteriori) to these questions begins well before planning the action, at the same time that the objectives of the program or action are defined, a model of expected impacts and a methodology for the collection are developed Of the data and their evaluation.

To show this circular process we have selected some models or guides for the evaluation with which we have elaborated the scheme reflected below:


Impact assessment is an instrument that contributes to decision-making and accountability, that is, it provides information for both managerial and citizen actors on the effectiveness of the programs to which a public budget is allocated .


If you want to know more …


Zewo Foundation (2011) Outcome and Impact Assessment in International Development. Zewo Foundation, Zurich 2011.

Cupitt, S. with Ellis, J. (2007) Your project and its outcomes. Charities Evaluation Services.

OECD. Outline of Principles of Impact Evaluation.

European Comission (2009) Impact Assessment Guidelines. 15 January 2009.

European Comission (2012) Design and commissioning of Counterfactual Impact Evaluations. October 2012.

Gertler, P. et al. (2011) Impact Evaluation in Practice. The World Bank.

En Español:

Ivàlua (2009) Guia pràctica 5. Avaluació d’impacte. Institut Català d’Avaluació de Polítiques Públiques.

Coneval (2009) Anexo 1: Guión del Análisis de Factibilidad para llevar a cabo una Evaluación de Impacto. Consejería Nacional de Evaluación de la Política de Desarrollo Social. México.