A synthesis of neo-Schumpeterian evolutionary, sociological, and historical coevolution ary models could be used for constructive technology assessment, aimed at the active management of the process of technological change. This article proposes a synthetic quasi-evolutionary model, in which variation and selection are neither independent nor coincidental processes. Variation and selection are linked by actors, resulting in the actor role labeled technological nexus. On the basis of the quasi-evolutionary approach, three constructive technology assessment strategies are proposed: stimulating alternative variations, changing the (...) selection environment, and creating or utilizing technological nexus. The usefulness of these concepts is demonstrated for the case of clean technolo gies. Ultimately, a conscious application of these strategies could result in a new actor role for government as a creative social regulator of technological change. (shrink)