The global recession associated with the 2008-09 financial crisis has triggered a wave of unprecedented fiscal and monetary interventions. Despite their wide use across the world, the quantitative effects of these large scale measures on the aggregate economy remain unclear. The main reason for this uncertainty is that governments and central banks have been unable, so far, to target the households and businesses more likely to boost the recovery: (i) some consumers may not spend their income tax rebate in the anticipation of future tax raises; (ii) part of the financial institutions may use the expansion of the central banks’ balance sheet to increase their capital ratio rather than lending; (iii) many import good producers may take advantage of fluctuations in the exchange rate to vary their price mark-up as opposed to passing it to customers; (iv) entrepreneurs may delay some investment projects until part of the uncertainty on their returns is resolved.This research aims at contributing to the growing empirical and theoretical literature on macroeconomic dynamics with heterogeneous agents by offering an empirical evaluation of the policies and macroeconomic conditions that prevailed during the financial crisis. The aggregate effects of individual heterogeneity will be quantified across groups of the society endogenously determined within the estimation method. Furthermore, there will be identified the characteristics that make some individuals more sensitive to the policy measures and more vulnerable to specific macroeconomic conditions. Mapping the estimated heterogeneity to observed characteristics can have an impact on both academic and policy research. On the academic front, the approach taken in this proposal will make it possible to discriminate among competing theories of heterogeneous behaviour. As for policy, knowledge of the characteristics that drive heterogeneous responses in the data can be used in future interventions to target the most sensitive groups of the population.