Darcy Ummels

148 | Chapter 7 protocol were met in the validation studies performed for this dissertation, thus ensuring methodological and reporting consistency and facilitating comparisons between activity trackers. Three proposed activities were not included in our study: computer use, smartphone use and simulated video games. Furthermore, cadence and gait velocity were not reported. As stated before, it is important to have insight into the validity of an activity tracker on both a group and individual level, depending on the goal of using the activity tracker. The validity on an individual level is important for the end ‐ users (e.g. healthcare professionals or older adults), whereas validity on a group level is more important to policymakers and researchers. Two guidelines propose statistical tests when validating a measurement tool in order to create standardisation. 25,26 In this dissertation both guidelines were applied to provide information on a group level as well as an individual level (state ‐ of ‐ the ‐ art validation). One limitation might be that this study did not assess the reliability of the activity trackers, which is also an important clinometric property. However, due to the structure of the validation protocols used, it was not possible to determine the reliability. The umbrella concept ‘feasibility’ During the course of this dissertation, a framework was developed in which the feasibility of activity trackers and other eHealth tools can be examined (found in the appendix to chapter three). The framework is based on the literature on the feasibility of activity trackers, the findings of this team’s own studies, and user and expert assessments. Feasibility is an important trait; if an activity tracker is not feasible, it will not be used persistently. However, feasibility is a broad term, referring to both patient and professional use as well as aspects of the measurement tool. It is possible that some aspects of the broad term ‘feasibility’ are not fully embedded in the current framework since it was evaluated within a relatively small group and a limited context. Thus, this framework is a first step to assess the feasibility of activity trackers in daily clinical practice and could be a ‘dynamic framework’, where aspects of feasibility in different contexts are added or adjusted as needed. Lessons learned The lessons that can be learned from this dissertation are described in relation to the following themes: ‘involving stakeholders is the key to success’, ‘measuring with an