User preferences and usability of iVitality: optimizing an innovative online research platform for home-based health monitoring

Figures & data

Figure 1 Schematic presentation of the iterative phases.

Table 1 Participant characteristics

Variable	Phase 1	Phase 2	Phase 3	Phase 4
	Interview 1 (n=3)	Focus group (n=6)	Interview 2 (n=2)	Usability evaluation (n=4)
Sex (male/female)	1/2	1/5	0/2	1/3
Age, years (male/female)	53/55, 62	53/42, 55, 58, 63, 64	50, 51	53/43, 61, 62
Highest education
Middle	1 of 3	4 of 6	–	3 of 4
High	2 of 3	2 of 6	2 of 2	1 of 4
Experience in using a	2 of 3	3 of 6	2 of 2	2 of 4
smartphone (n)
Experience in using	3 of 3	6 of 6	2 of 2	4 of 4
Internet (n)

Notes: Two participants of the first interview also participated in the focus group, making a total of 13 participants. Highest education can refer to: middle education (secondary school + vocational education) or high education (higher vocational education or university).

Figure 2 (A) Blood pressure measurements in original iVitality smartphone application. (B) Blood pressure measurements using reference lines as requested by participants.

Table 2 Usability tasks concerning application of iVitality

Description of usability tasks	Results based on think aloud and participant’s performance	Participant’s reported experience indicated by “x”
		1	2	3	4
1. Monitoring and registering blood pressure data with the iVitality application.	User had a problem in interpreting the menu navigation structure of the application when searching how to register the blood pressure results.	x	x	x	x
	The “back-tip” to undo a mistake did not work.	x	x	x	x
	Bluetooth asked for authorization. The user was confused and thought the data were visible to more people.	x
	The application announced “busy gathering data” instead of “start blood pressure measurement” which confused the user.	x	x	x	x
	After the first measurement, the user thought he/she could continue immediately with the second measurement.		x
	Internet, or Wi-Fi connection was needed to see the instruction video via the iVitality application. The user did not know this.		x
2. Comparing the new measured blood pressure data with those measured before.	Graphical presentation was not clear for users; users could not read the former measured blood pressure values from the smartphone display.	x	*	x	x
3. Measuring physical activity.	Physical activity sensors are always active when running the iVitality application. The user did not know this and was not able to see this.		x
	Wearing the iVitality application daily for physical activity was no problem.	x	x	x	x
4. Version 1: graphical presentation of measured blood pressure data and a black reference line of maximum permitted value according to participant’s age group.	The user believed that the black line was the mean blood pressure of the whole study group. The representation of one’s own value above this line was not conceived as a problem.	x	x	x	x
5. Version 2: graphical presentation of measured blood pressure data and both gray and black reference lines of “high” and “maximum” permitted values.	The user did not understand the meaning of the gray line. The user found two reference lines too much for a good orientation.	x	x	x
6. Choosing only the one line or both references lines.	See point 5. The user preferred to maintain only one reference line for early detection of having a “higher” blood pressure.		x		x
7. Feedback: which text do you prefer? And would you undertake action?	Feedback “light increase”, “high”, or “severe” blood pressure is appreciated.	x	x	x	x
	Would undertake action when feedback provided “high” or “severe” blood pressure.				x
	Would undertake no action when feedback was “little increase”.	x		x

Note:

* No data available.

Table 3 Perceived ease of use and quality of the iVitality smartphone application for four participants (PSSUQ)

Domain	Number of questions	Response rate per domain (%)	Mean score (SD)
System ease of use and efficiency	10	100	5.50 (1.71)
Satisfied about ease of use and understanding how to use	5	100	5.25 (1.97)
Efficiency in doing tasks	5	100	5.75 (1.41)
Information quality	6	100	5.96 (1.63)
Error handling, information easy to understand, information helpful in doing tasks
Interface quality	8	87.5	5.68 (1.83)
Letter quality, contrast, colors, easy to read, easy to learn how it works

Notes: Outcomes are measured on a 1–7 scale; higher scores refer to higher agreement.

Abbreviations: PSSUQ, Post-Study System Usability Questionnaire; SD, standard deviation.

Table 4 Motivation in using iVitality for four participants (TSRQ)

Domain	Mean per question	Response rate per domain (%)	Mean score (SD)
Autonomous responses using iVitality		96	5.44 (2.42)
1. I feel it is a personal challenge	1.3
2. I made this choice on my own	7.0
3. I think I have benefit as a child of a demented elder	5.5
4. I find this important	7.0
5. I find this important for having insight into my condition	5.0
6. I like taking responsibility for my own care and/or lifestyle	5.0
7. I really believe it is the best thing for me to do	7.0
Controlled responses using iVitality		95	1.32 (0.67)
1. I would feel bad about myself if I did not	1.8
2. I want others to approve of me	1.3
3. I want my partner and significant others to not be disappointed	1.0
4. I want my physician to see me as a “model” patient	1.0
5. I would feel guilty if I did not	1.5

Notes: Outcomes are measured on a 1–7 scale; higher scores refer to higher agreement.

Abbreviations: TSRQ, Treatment Self-Regulation Questionnaire; SD, standard deviation.