The effect of a public policy refers to the change, intentional or otherwise, produced, directly or indirectly, by that policy on a given variable in relation to the beneficiaries. This change is measured with respect to the value the variable would have had if the policy had not been adopted and implemented.

The term evaluation has many and varied meanings, as a result of the different methodological approaches adopted in the literature.. Very briefly, evaluation can be defined as an objective judgement (i.e., based on a scientifically rigorous approach) of a planned, ongoing or completed public policy (see intra). This judgement is intended to respond to specific questions regarding the design, implementation or results of the policy in question. According to some commentators, the presence of a judgement is the basis of the distinction between the activity of analysis and that of evaluation. The former expresses a positive approach, i.e. one that merely describes the reality as it is, while the second expresses a normative approach, i.e. one that is intended to suggest how the reality should be. The judgement expressed by the evaluation has an essentially informational function, however, which is intended to improve the policy and, more generally, to make better use of public resources. An example is the value for money approach that is typical of the Anglo-Saxon world and which is designed to investigate whether the results of a given policy are worth the public resources employed in it. The informational nature of the judgement resulting from the evaluation is the basis of the difference between the evaluation and the control functions. In the latter, the judgement of the body controlling the study is intended essentially to hold the body controlled accountable. However, the results of the evaluation can be a cognitive condition for subsequent controls.

Depending on when the evaluation is expressed with respect to the policy under examination, we can distinguish between ex ante, ongoingand ex post evaluation. The first refers to an intervention at the planning stage, the second examines a policy during implementation - but with a different informational intent that mere monitoring (see intra) - and the third to a concluded action.

Depending on the object of the judgement linked to the evaluation, we can distinguish between process evaluation and impact evaluation. The former examines the policy implementation (see intra) mechanisms, including with a view to evaluating whether or not the results correspond to the objectives. The latter focuses on the effects of the policy and seeks to reconstruct the cause-effect linkages between the intervention and the observable results. In other words, it seeks to verify whether any changes seen in the reality can be attributed to the effects of the policy, and not to other causes. The evaluation of the effects can be based on a counterfactual approach (see intra), i.e. a comparison of the observation of reality as it is (by measuring given variables) and an estimate of how it would have been in the absence of the policy.

Sources:

- World Bank, Impact Evaluation in Practice, Washington 2011, p. 7 et seq.;

- Martini A. and Sisti M., Valutare il successo delle politiche pubbliche, Bologna 2009, p. 21 et seq.;

- La Spina A. and Espa E., Analisi e valutazione delle politiche pubbliche, Bologna 2011, p.31 e ss. e p. 181 et seq.

This is the dimensions of parliamentary oversight that takes place before Government formally adopts a decision, an initiative, or a certain public policy. Parliament scrutinises Government's proposals or draft documents in order to guide future policy choices and exert an influence on the sphere of action of Government.

For further details, see: Parliamentary Oversight

This is the dimension of parliamentary oversight comprising follow-up action through which Parliament holds the Government to account for past decisions and/or actions. It may be associated with a system of sanctions, e.g. a no-confidence vote. Its main aim is to enforce the statutory accountability of Government before the representatives elected by the people and public opinion.

For further details, see: Parliamentary Oversight