Drawing on a large database of publicly announced R&D alliances, we track the evolutionof R&D networks in a large number of economic sectors over a long time period (1986-2009). Our main goal is to evaluate temporal and sectoral robustness of the main statisticalproperties of empirical R&D networks. By studying a large set of indicators, we providea more complete description of these networks with respect to the existing literature. Wefind that most network properties are invariant across sectors. In addition, they do notchange when alliances are considered independently of the sectorsto which partners belong.Moreover, we find that many properties of R&D networks are characterized by a rise-and-fall dynamics with a peak in the mid-nineties. Finally, we show that suchproperties of empirical R&D networks support predictions of the recent theoretical literature on R&D network formation.
