2.4.2. Suggesting a Coaching Domain and Goal

Users that are assigned to the coaching category are guided by the Active2Gether system to focus their behavior change efforts, by advising on the choice of a specific coaching domain and a goal. This cycle is repeated on a weekly basis. The coaching domains are parts of the user's daily life: (1) stair use at significant locations (e.g., home, work, and university); (2) active transport to significant locations; and (3) leisure-time sports activities.

First, detailed information about the user's context and behavior is used to identify in which domains the user could be more physically active. The user's physical activity in each of the three domains is estimated based on a combination of activity data collected through the activity monitor (number of stairs climbed) and daily user input through the app (selected transport options to visited locations, time spent on sports activities). These physical activity values are then evaluated by comparing them to estimated "maximum" or "ideal" values, which are based on information about the user's context and visits to their important locations. This context information is collected through an intake questionnaire, and includes information about the addresses of their significant locations, (active and non-active) travel options between these locations, relevant floor numbers on these locations, and the availability of stairs. For example, if a user works on the third floor and on average climbs another three floors during the day, a total number of six floors during a work day would be reasonable. For a user that works on the second floor, but on average climbs another eight floors during a work day, a total number of six floors is comparatively low. In addition, the more often the user has gone to work, the higher the expected number of stairs becomes. Similar evaluations are developed for the physical activity level in active transport and sports activities. Using these evaluations, the domain with the largest potential for improvement can be detected, as the evaluation score for that domain will be lowest. This domain is then suggested to the user as focus for the coaching in the upcoming week. However, the user is allowed to overrule this suggestion and opt for another domain.

After selection of a coaching domain, the user is asked to set a specific goal for this coaching domain, i.e., weekly time spent on active transport, weekly time spent on sports or daily number of stairs climbed. If users did meet the previous goal in this coaching domain, the system suggests increasing their goal by 10%. If users did not meet the goal last time, the system advises to keep the goal at the same level. Again, to ensure the user's autonomy, the final decision on the goal is up to the user.

This relative evaluation of the user's behavior and the recommendation of a certain coaching domain respect the individuality of the users more than general physical activity guidelines. It prevents the system from imposing the same expectations on all users, even though their personal situations may be completely different.
