Table 4.

Illustrative quotes regarding the UIs from participants who used the optimized UI and the basic UI respectively.

Item		Optimized UI	Basic UI
Likable	Positive aspect	“It was great to work with all steps within the intervention, and to complete one step at a time before heading to the next one. It was also good that I was able to return to previous steps and that the information I had entered was editable.” ID 101	“It is easy to use, and it is designed in a way that helps you to formulate problems as well as think of different solutions.” ID 112
	Negative aspect	“I think that there were too many steps. To set goals felt unnecessary. It complicated the use.” ID 102	“It was hard to use the intervention digitally, due to small text boxes and bad overview.” ID 113
Easy to understand	Positive aspect	“The instructions were well formulated, and it was evident what was expected of me.” ID 103	“I think that the instructions were very clear and simple.” ID 114
	Negative aspect	“I would have preferred a simpler and more compact version of the intervention. It felt unnecessarily complex and my impression was that it took too long before I actually got somewhere.” ID 104	“The intervention is a bit bulky and old-fashioned. A more user-friendly system would have been good!” ID 115
Relevant examples	Positive aspect	“Great examples. Many different types of problems are covered and you get a good understanding of how to think. It was good that the examples could be unfolded when not needed, so that they did not obstruct working with the intervention.” ID 101	“I returned to the examples several times. The examples describing simple problems, such as cleaning, were good since they made me not feel stupid about my own problems, and they made it easy to understand what to do.” ID 116
	Negative aspect	“I understand the purpose of including examples, but the examples are not that advanced or difficult.” ID 105	“I think that the examples should be optional and possible to expand. It is way too much text as it is now.” ID 117
Overwhelmed	Positive aspect	“As with all new digital tools, it takes a while to get used to it, as with everything you do for the first time. But it is not difficult at all. It is very logically described. One step at a time. Great!” ID 101	“Extensive introduction. But when one had managed to finished it, it was clear to me what I was going to do.” ID 118
	Negative aspect	“The introduction was too long and complicated.” ID 106	“There was too much information in the beginning, and everything was presented at once. It felt overwhelming.” ID 119
Suggestions of possible improvements		“Daily notifications reminding the user that it is time to work with the intervention.” ID 107 “The possibility to print the content.” ID 108 “Supervision and follow-up with a real person. Feedback and support.” ID 109 “Lists with suggestions of problems to choose from, together with suggestions of solutions to those problems.” ID 110 “Video clips comprising instructions.” ID 111	“Less amount of text. Information divided it into foldable sections.” ID 117 “Better adaptation to mobile phones, to decrease the amount of scrolling needed.” ID 120 “More suggestions on how to work with problems.” ID 121 “Help-texts, and pop-ups with explanations.” ID 122 “Information presented in a more interactive manner.” ID 123

Same row does not indicate that the quote is from the same participant.