Hardly anyoee will dispute that the creation of theScience Citation Index has made an important difference to science. It is less clear, however, in what way the science system has been influenced. This article proposes a qualitative model to better understand the mutual interactions involved. Science is pictured as an information processing cycle. Its quality is maintained in the “peer review cycle”. The main upshot of theSCI has been the creation of a second-order cycle on top of the primary knowledge production cycle. This is the citation cycle. The specialty of scientometrics has a key role in this citation cycle. The model enables a more profound understanding of the various feed back processes between the two cycles. Moreover, it may give insight in the development of hybrid and heterogenous scientific specialties like scientometrics.