There is no generally accepted method of measuring performance of an innovation system. The measurement of the performance of an innovation system influences policy decisions for the improvement of such a system and makes comparisons possible. The question arises how the complexity of an innovation system should be addressed in the measurement of the performance of the system. A descriptive analysis is made of empirical studies that measured innovative performance. The use of composite indicators has become more popular. Unfortunately, many existing indices that intend to measure innovative performance comprise capacity and performance indicators where they should rather focus on performance indicators such as innovation count and innovation surveys.