The influence of social conditions on school performance is not new to science. This research was prompted by the lack of quantitative studies with data released by the IBGE (Brazilian Institute of Geography and Statistics) and INEP (Anísio Teixeira National Institute of Educational Studies and Research) relating to education and the social conditions of the Brazilian population as a public management planning tool. The objective was to analyze the extent to which social conditions affect school performance. For this, we used linear regression between the variables Poverty Incidence and Average value of IDEB (Basic Education Development Index), for municipalities in southern Brazil with less than 10,000 inhabitants and that present both variables. As a result, the values indicate that there is an inverse relationship, showing that as the values for Incidence of Poverty increased, the Mean values of the IDEB decreased. Another aspect revealed in the survey is the difference between the results for the South region and the analysis of each Federal Unit that comprises the Region separately, indicating a weakness in large proportion statistical analyses.