In the landscape of social research, the case study method is considered an effective tool for analysing complex phenomena with multiple dimensions. The case study is indispensable when the analysis focuses on unique and unrepeatable cases (e.g., a reform) for which the use of other methods may be reductive. In the context of policy analysis and evaluation, the case study can be used to examine a programme, intervention or policy to analyse its effectiveness, impact and implementation. It is particularly valuable when the research objective is to understand the "how" and "why" of a social phenomenon, providing insights into processes, outcomes and the experiences of the actors involved.

A central element in the use of this method is the selection of cases for analysis, which must be justified and framed within a well-defined theoretical framework. The literature offers various criteria for case selection. The two main ones are: maximisation and minimisation of differences. In the first case, the interest is to identify common elements by also studying deviant or extreme cases, while in the second, the focus is on very similar cases that differ only in one aspect (e.g., the policy of interest). This approach makes it possible to analyse how the same policy is perceived in very different contexts or what its effects may be.

The next phase is data collection, for which it is preferable to obtain information from multiple sources to ensure the triangulation of information with the goal of enhancing validity. Common methods include in-depth interviews with stakeholders, beneficiaries, and experts; document analysis; as well as collecting data through surveys to complement the qualitative evidence. In some situations, participant observation may also be used, in which the researcher is directly involved in the activities being studied.

In the data analysis phase, techniques such as coding qualitative data are used to synthesise information and make it generalisable, but the real challenge is to integrate and organise the many pieces of information collected. The aim is to construct a detailed narrative that explains the case comprehensively and coherently, considering all the key variables at play.

The main limitations of this method are the time and resources required. In addition, it can be subject to researcher bias due to the interpretive nature of the analysis, and the results often lack external validity due to the focus on specific cases.

However, the advantages of the case study include its ability to provide an in-depth understanding of complex phenomena and policies, to capture context-specific insights, and to generate rich qualitative data that can also contribute to theoretical development.

It is a dimension of parliamentary oversight implemented through public debates, parliamentary reports and the use of the media. Its main aim is to grant transparency of governmental action vis-à-vis public opinion. It is based on a combination of both formal and informal parliamentary prerogatives in the field of information and communication.

For further details, see: Parliamentary oversight

The cost-benefit analysis (CBA) is a method used to compare alternative public intervention options. It is normally carried out before the intervention (ex ante) to decide whether the intervention should be financed, but can also be carried out ex post, as an evaluation tool. The CBA compares the social benefits and costs of each alternative. An intervention is judged to be desirable if, overall, the benefits exceed the costs. The option to intervene is therefore implicitly compared with the alternative of leaving the current situation unchanged (status quo or "option zero"). If there are several intervention options, the one with more benefits than costs is deemed to be preferable. In the CBA, after defining the scope of analysis (geographical context, intended beneficiaries and timeframe), the relevant costs and benefits are identified. The amount is estimated and expressed in monetary units (monetisation) with a view to facilitating comparison. The CBA is not therefore suitable for use with non-monetisable values. In such cases, to make the comparisons, the cost quantification should be crossed with an estimate of the results of the intervention, as happens in the cost-effectiveness analysis (CEA) (see intra).

Sources:

- Momigliano S. and Giovanetti Nuti F. (ed.), La valutazione dei costi e dei benefici nell'analisi d'impatto della regolazione, Soveria Mannelli 2001, pp. 36-46;

- World Bank, Impact Evaluation in Practice, Washington 2011, p. 230.

Cost-effectiveness analysis (CEA) makes it possible to compare alternative policies on the basis of their costs and effectiveness. Since costs (monetised) and results (not monetisable, such as the number of human lives saved by a given prevention policy in the health sector) are being compared, it is not possible in the CEA to calculate the balance between the monetary value of the costs and the benefits, as happens in the CBA (see intra). Cost-effectiveness indices (such as the average cost per unit of result, or the result per unit of cost) must be constructed, through which the different policies can be compared.

Source:

- Momigliano S. and Giovanetti Nuti F. (ed.), La valutazione dei costi e dei benefici nell'analisi d'impatto della regolazione, Soveria Mannelli 2001, p. 47 et seq.;

- World Bank, Impact Evaluation in Practice, Washington 2011, pp 11-12 and 230.

Counterfactual refers to the value that the result variable would have had if the public policy in question had not been adopted and implemented. Precisely because it refers to a situation that did not occur, the counterfactual cannot be observed.