Developing the theoretical principles of the QET
The theoretical principles are intended to illustrate how the QET is related to basic theories of restorative environments and to clarify the theoretical evidence-based nature of the QET. Theories and models were selected that have implications either for general design or for constituents of outdoor environments in healthcare settings. One theory was used as the foundation, and other theories and concepts were then related to this theory using a set of models. These models formed the basis for developing the practical structure of the QET.