After all, how many companies are there in this town?

Barueri is a small country town, located to the west of São Paulo City. The town offers tax exemptions to companies that set up business there, becoming an important industrial area and cluster. As a consequence, Barueri has filled up with paper companies, that is, companies that exist only for formal burocratic purposes, but which do not really conduct their operations there. The task of identifying which companies really conduct their operations in the town is difficult. Frequently, a contact with a company with headquarters in Barueri results in dealing with a professional accounting office professional which represents it, with the organization effectively being located outside the town. The Presbyterian Mackenzie University intended to establish relationships with companies of the region, considering the plans of development for the Tamboré Campus, located in Barueri. Consequently, it was essential to define a universe and a sample of companies whose operations occurred in the surrounding area of the Campus in order to establish partnership programs. It was therefore faced with the challenge of finding which companies were effectively located in Barueri, since paper companies have no interest in the development of the campus. How to find them?