Most of innovation studies and researches are not related to innovation measurement and, in general, it only addresses some innovative actions in terms of products, services or processes. This paper addresses the difficulties in researching innovation and Open Innovation (OI) performance metrics through an exploratory literature research followed by a survey conducted with small technology-based enterprises incubated at important Brazilian industrial and technological centers. It is well known that for many small business entrepreneurs and managers, the idea of OI practices are still restricted to large corporations. Against this idea, this work proposes an understanding of these OI practices, besides an analysis of its measurement. The indicators proposed by this work developed with the support of the statistical technique of factorial analysis, has been proved to be the most significant to measure OI at this kind of company and, with them, it has been possible to understand that small companies can successfully use OI and, although it is not common today, it should be encouraged. This study’s conclusions can be useful for researchers and Small to Medium Enterprises (SMEs) interested in joining or increasing their OI practices.