The Arena and NCE programs have recently been subjected to thorough evaluations by Menon and NIFU (2011) and Econ and Damvad (2011) respectively. This article sums up the most important findings from these evaluations. Our main point of focus will be the programs’ capability to develop and strengthen cluster characteristics in business environments. In this article, we develop a conceptual model for cluster-based innovation and growth which illustrates how cluster programs influence interaction in business environments. The conceptual model and the framework of understanding the model provides are utilized both in the presentation of the results from the two evaluations, and in a more open, general discussion of Norway’s cluster programs.