Declining inequality in Latin America? Robustness checks for Peru

Abstract

Household surveys underreport incomes from the upper tail of the distribution, affecting our assessment about inequality. This paper offers a tractable simulation method to deal with this situation in the absence of extra information (e.g., tax records). The core of the method is to draw pseudodata from a mixture between the income empirical distribution and a parametric model for the upper tail, that aggregate to a preestablished top income share. We illustrate the procedure using Peruvian surveys that, as in the rest of Latin America, have displayed a sustained decrease in the Gini index since the 2000s. In a number of experiments, we impose a larger top income share than the one observed in the data, closer to corrected estimates for less egalitarian neighbors (e.g., Colombia and Chile). We find that even though the point estimates of the Gini index are biased, the corrected indices still decrease in time.