Health informatics projects often develop innovative IT solutions for health care. Systematic evaluation of their impact and risks is an ethical imperative. However, field studies can often not be conducted because of immature solutions. On the other site, lab studies are not helpful when it comes to estimating the impact of an innovative IT solution. We faced this challenge within the PSIP projects where innovative tools for medication management are developed. In this paper, we present the approaches used within the PSIP project for estimating the impact of immature solutions, including surveys of future users, a Delphi study with experts, and a simulation study. The methodology and first results of those evaluations are presented, and lessons learnt for impact evaluation of immature solutions are discussed.