Quantitative ex-post analysis methods for state aid

State aid remains a frequently deployed yet controversial policy instrument within European public policy. The ex-post assessment of such measures is crucial for understanding their true effectiveness and impact on both beneficiaries and the wider market. This paper proposes a quantitative evaluation of the impact of state aid provided to Romanian companies, using the Difference-in-Differences model alongside robust methods such as Regression Discontinuity Design and Propensity Score Matching. The primary goal is to isolate the net effect of public support on key economic company indicators like turnover, employment, and investment. The paper stresses the importance of the careful selection of control groups and validation of methodological assumptions, while also acknowledging the challenges posed by data availability and the complexity of the economic environment. The conclusions point to a positive but uneven impact of state aid, offering recommendations for refining public policy and embedding ex-post evaluations in the policy cycle.