RESUMEN
Democratic accountability implies that citizens incentivize politicians by rewarding them electorally for beneficial policy. While we know little systemical about the time horizons voters employ for their retrospective evaluations, many observers worry that voters are notoriously myopic and that this short-term bias creates perverse incentives for public policy. We exploit the policy response to the 2002 Elbe flooding in Germany as a natural experiment to dynamically estimate the short- and long-term electoral returns to beneficial policy. Given the well known "peak-and-end-rule" for forming retrospective judgments, the Elbe flooding provides an ideal case to establish an upper bound for the longevity of voter gratitude since the incumbent's flood response was both massive and occurred immediately prior to a federal election. Using a difference-in- differences identification strategy we find that the flood response resulted in an immediate electoral gain for the incumbent party of about 7 percentage points in affected areas in the 2002 election. We also find that 25 percent of this short-term return carries over to the 2005 election. By 2009, however, the electoral gains are entirely vanished. Overall our results suggest that even though electoral returns to beneficial policy decay dynamically over time, policymakers, at least given very favorable circumstances, can generate voter gratitude that persists several years - perhaps longer than scholarship has acknowledged so far. We elaborate on the implications of our findings for democratic accountability and public policy.