Social Closure and Occupational Diversity in the Brazilian Federal Legislature: Comparing the Chamber of Deputies and the Federal Senate (1998–2022)

Abstract

This article examines the institutionalist expectation that proportional representation and the larger number of seats in the Chamber of Deputies would yield a more diverse occupational composition than the majoritarian rule of the Federal Senate. The analysis covers 3,861 records of deputies and senators elected between 1998 and 2022. To compare houses with very different numbers of members, we apply rarefaction, a technique that allows groups of equal size to be compared, together with the Simpson and Shannon indices. Long established in population ecology for the study of biodiversity, these two measures capture the balance and variety of the occupational categories represented in the legislature. The results run counter to the institutionalist expectation: the Chamber does not display greater occupational diversity, and the indicators favor the Senate in six of the seven elections examined. This pattern, however, varies with the election and with the granularity of the occupational classification. The Theil index, which measures the extent to which occupational composition varies across ideological blocs, further shows that left and right present only weakly differentiated occupational profiles in both houses, contrary to the expectation that ideological divisions would translate into clearly distinct occupational bases of recruitment. The data also reveal a pronounced shift in the profile of those elected: the share declaring political occupations rose from roughly 25% to more than 50% over the period, signaling the advance of political professionalization. Taken together, the findings show that differences in electoral rules do not translate automatically into greater occupational plurality. Explaining the observed profiles will also require future attention to the social profile of those who run for office, the criteria parties use to select their candidates, and the circulation of professional politicians between the two houses, particularly the recruitment of senators from among former federal deputies.