Tests conducted prior to a Population Census are of fundamental importance for the success of the operation, since they allow the development of strategies intended to improve quality of information. With the purpose of evaluating some hypotheses that may account for possible errors or blanks in the preceding investigation and of fulfilling demands from specific topics, several tests have been conducted, such as one on the question about color or race (2016), one on the quilombola ethnicity (2016) and another on the investigation of autism (2019).