This paper contributes to the literature on the methods investigating the causal channels determining the impact of a specific event (e.g. the introduction of a public policy, a firm bankruptcy or a natural disaster).
This paper introduces a new method to investigate the causal mechanism determining the impact of a specific event. It can be applied when the number of units observed is too low to use the existing methods. An application of the new method is also provided, evaluating the consequences of an anti-smoking policy (California's Proposition 99).
