Recent emphasis on credible causal designs has led to the expectation that scholars justify their research designs by testing the plausibility of their causal identification assumptions, often through balance and placebo tests. Yet current practice is to use statistical tests with an inappropriate null hypothesis of no difference, which can result in the equating of non-significant differences with significant homogeneity. Instead, we argue that researchers should begin with the initial hypothesis that the data is inconsistent with a valid research design, and provide sufficient statistical evidence in favor of a valid design. When tests are correctly specified so that difference is the null and equivalence is the alternative, the problems afflicting traditional tests are alleviated. We argue that equivalence tests are better able to incorporate substantive considerations about what constitutes good balance on covariates and placebo outcomes than traditional tests. We demonstrate these advantages with applications to natural experiments.

In this paper, we show that Brazilian voters strongly sanction malfeasant mayors when presented with hypothetical scenarios but take no action when given the same information about their own mayor. Partnering with the State Accounts Court of Pernambuco, we conducted a field experiment during the 2016 municipal elections in which the treatment group received information about official wrongdoing by their mayor. The treatment has no effect on self-reported voting behavior after the election, yet when informing about malfeasance in the context of a vignette experiment, we are able to replicate the strong negative effect found in prior studies. We argue that voters’ behavior in the abstract reflects the comparatively strong norm against corruption in Brazil. Yet on election day, their behavior is constrained by factors such as attitudes toward local political dynasties and the greater salience of more pressing concerns like employment and health services.

One of the most robust findings on political institutions is that compulsory voting (CV) reduces the participation gap between poorer and wealthier voters. We present evidence that in Brazil, the largest country to use such a rule, CV increases inequality in turnout. We use individual-level data on 140 million Brazilian citizens and two age-based discontinuities to estimate the heterogeneous effects of CV by educational achievement, a strong proxy for socioeconomic status. Evidence from both thresholds shows that the causal effect of CV on turnout among the more educated is at least twice the size of the effect among those with less education. To explain this result, which is the opposite of what is predicted by the existing literature, we argue that nonmonetary penalties for abstention primarily affect middle- and upper-class voters and thus increase their turnout disproportionately. Survey evidence from a national sample provides evidence for the mechanism. Our results show that studies of CV should consider nonmonetary sanctions, as their effects can reverse standard predictions.

To enhance government accountability, reformers have advocated strengthening institutions of “horizontal accountability”, particularly auditing institutions that can punish lawbreaking elected officials. Yet, these institutions differ in their willingness to punish corrupt politicians, which is often attributed to variation in their degree of independence from the political branches. Taking advantage of a randomized natural experiment embedded in Brazil’s State Audit Courts, we study how variation in the appointment mechanisms for choosing auditors affects political accountability. We show that auditors appointed under few constraints by elected officials punish lawbreaking politicians—particularly co-partisans—at lower rates than bureaucrats insulated from political influence. In addition, we find that even when executives are heavily constrained in their appointment of auditors by meritocratic and professional requirements, auditors still exhibit a pro-politician bias in decision making. Our results suggest that removing bias requires a level of insulation from politics rare among institutions of horizontal accountability.