The model of Evidence-Based Practice (EBP) is originally designed as a tool for clinical problem solving and work related learning. According to its theory of use EBP will bring an ethically sound and effective practice. Although simple in its construction implementation of the model seems as a highly complex and tricky activity in the field of social work as well as in the field of healthcare and others. The paper addresses how actors on different analytical levels respond to, translate, and spread the EBP-model. This is argued to be an effective cause to the overall implementation effect, which includes differentiation and sidesteps from the basic model. Also contextual factors hinder or facilitate realization of the model in practice, either if it will be the original model or translations of it. In sum this analytical framework of how adoption of a new practice model can be understood and explained also gives rise to the provoking question whether adherence with the original EBP-model is desirable and realistic in the context of social work. If so, a necessary follow-up question would be how fidelity with the original EBP-model can be secured. The paper explores different approaches in program theoretical terms. Empirical examples from debate and implementation efforts are given.