There is a strong common sense about the importance of user-participation for business process transformation: changing processes means changing the way people do their work. Hence, involving users early enough in order to get their support and input appears to be vital for business transformation. Or – the other way around: in case people are resistant to change, it is very likely that economic targets will not be met and quite often projects even turn out to fail. However – in spite of this intuitive understanding – little academic evidence is to be found on the leverage of user participation. Hence, with this study we set out providing some more evidence for the leverage of user participation in business process transformation. In the context of five case studies, we were able to compare transformation projects with different degrees of user participation and also to relate this to the results of these projects. In addition to the level of acceptance mobile tools introduced in the project we were also able to study the impact on KPIs.