*3.5. Selection and Tailoring of Coaching Messages*

The messages that people receive are very diverse, but sometimes still give the impression that they are redundant or not on topic. For a more detailed investigation of the user experience of the messages, see [8]. We have a number of suggestions for improvement.

First, the personal relevance of the messages could be improved. For example, the messages are only sent at specific times during the day, but the users' physical location could be used to trigger messages as well. Furthermore, the selection of messages to be sent could be based on more complex combinations of information. For instance, combining the current location with the relevant floors on that location and the availability of stairs and the maximum number of stairs that a user is willing to walk. Incorporating these ideas would increase the context-awareness of the system. In addition, the messages should contain less trivial content in order to better fit the expectations of the target group.

Next, we implemented the selection of the message to be sent in such a way that the system sends the message that has been sent the longest time ago. However, if only a few messages are relevant, the users will still receive the same messages in a short time period. Therefore, it is important to adhere to a minimum amount of time between resending the same message. In addition, the interdependence or similarity between messages should be taken into account: if messages are different formulations of the same content, the system should be aware of that. If such improvements imply that a user does not receive any coaching messages for some period of time, the system could observe this and send a warning to the developers to make sure that this lack of relevant messages is noticed and possibly remedied.

Finally, the coaching messages could be improved by implementing a feedback mechanism. Instead of only being able to click "OK" to close a message, the user could rate the message, and this feedback could be used to further tailor the system.
