Table 3.

Major usability issues and resolutions per round of testing.

Round	Type of problem	Problem emerged	Resolution
1	Layout	Information on increasing the font size was overlooked	Information was made more apparent
	Content	The work/school questions in the SQUASH were annoying and answered incorrectly	The answer option: “I do not have a job/I do not go to school” was added to skip the remaining job/school questions
		The assessment of intention and stages of change was perceived as unnecessary and because of that frustrating	A short explanatory introduction was added
		Program and feedback messages too lengthy	[no quick solution]
	Navigation	Scrolling after increased font size	[no quick solution]
2	Layout	Participant clicked in the wrong check box, when filling out answer options	An empty line was inserted after each 3 lines
	Navigation	Participants noticed the option to change font size, but did not succeed changing it	Instruction was simplified
	Content	The work/school questions in the SQUASH were annoying and answered incorrectly [solution not sufficient]	1. A warning to fill out the answer option:” I do not have a job/ I do not go to school” was added 2. A short overview of the questions was added 3. The sequence of the questionnaire was changed
		The assessment of intention and stages of change was perceived as unnecessary [solution not sufficient]	One question was removed
		Some feedback on physical activity disturbed the participant suffering from severe COPD	[no quick solution]
3	Navigation	One participant had problems changing the font size [solution not sufficient]	[no quick solution]