Joel W. Johnson, "Presidential Elections and Corruption Perceptions in Latin America," Journal of Politics in Latin America 7, 1 (2015): 111-142.
Abstract (full text available):
This paper argues that perceptions of corruption in Latin America exhibit predictable fluctuations in the wake of presidential turnover. Specifically, presidential elections that result in the partisan transfer of power are normally followed by a surge-and-decline pattern in perceived corruption control, with initial improvements that fade with time. The causes are multiple and stem from the removal of corrupt administrations, public enthusiasm about administrative change, and the relative lack of high-level corruption scandals in the early phases of new governments. A statistical analysis of two widely used corruption perceptions indices demonstrates the pattern for eighteen Latin American democracies from 1996 to 2010. Both indices exhibit a temporary surge (of about two years) after turnover elections, while no such change follows reelections of incumbent presidents or parties. The theory and results are relevant for understanding public opinion in Latin America and for the analysis of corruption perceptions indices.
This made me think of Brazil. Dilma Rousseff is drowning in a corruption scandal and trying to send bills to the legislature to convince people she's serious about fighting it. It's fair to say that few Brazilians will respond positively. At some point there will be presidential turnover and the new president will trumpet new anti-corruption measures. Public confidence will increase, then likely fade again. Wash, rinse, repeat.