Adaptation in Pervasive Computing normally focuses on services or on application behaviour, but the consideration of lower level algorithms in this process can lead to significant performance increase. To perform adaptation of algorithms the concept of context normally used in Pervasive Computing has to be extended. Based on the same context, group formation models are established to group devices with similar relevant context to optimise the adaptation process. In this paper, such group formation models are developed and evaluated. We also draw general conclusions for adaptation.