Technical change is crucial for sustainable development. Yet, it is unclear what kind of technology policy would suit such development. In this article constructive technology assessment (CTA) is offered as a model. CTA proposes broadening design by bringing together all interested parties early on and throughout the design process. CTA activities are not automatically directed at substantive goals such as those incorporated in the notion of sustainable development. The purpose of CTA is to shape technology development processes in such a way that social aspects are symmetrically considered in the process itself. To evaluate and shape CTA processes three criteria are offered: anticipation, reflexivity and social learning. These criteria are applied to three case-studies to illustrate their usefulness.