Success in implementation in early mathematics education - Fidelity and/or adaptation?

In this paper, the tension between fidelity and adaptation is elaborated on within the context of a large-scale implementation of a preschool mathematics innovation. We elaborate on how fidelity and adaptation can be understood in relation to depth, sustainability, spread, and shift in ownership. The results show that fidelity may hinder ownership while adaptations, when they are productive, may indicate depth, spread, sustainability, and ownership and thus be empirical evidence of successful implementation. The challenge in implementation research, then, becomes to clarify what adaptations that may be productive as they do not distort the core elements of the innovation. These results must, however, be seen in the context of Swedish preschool, where preschool teachers are qualified and expected to make productive adaptations in relation to the children they teach.