When asked for their preference for the add liquid intake, 11 participants (55%) preferred the mugs, 6 participants (30%) preferred the measurement jug, and 2 participants (10%) preferred the empty bottle option. One participant (5%) preferred the add a drink via button option (see Figure 4.13 in Section 4.6.2) as the main screen to add a liquid intake.
To read tips, 16 participants (80%) preferred reading the tips based on topic, and 3 participants (15%) preferred reading the tips all in one screen. One participant (5%) did not make a preference and did not make any suggestions to improve the design.
There were not many differences in participants’ preferences for the view progress options.
Eight participants (40%) preferred displaying the daily liquid consumption and the overall average liquid consumption and 10 participants (50%) preferred displaying only the daily liquid consumption without the average liquid consumption. One participant (5%) suggested displaying a graph of the seven latest liquid consumption only. The remaining two participants who did not have a preference or suggestions were concerned about the usability issues of the screen more than offering a preference, as exemplified by the following comment: “I'm colour blind … I can't see the red and green” (P6).
5.4 Discussion
This study reports on the user-based evaluation with 20 older adults of the MyDrinkApp prototype to support older adults in monitoring their liquid intake. The iPad prototype produced 214 instances of usability problems, a disappointingly large number. The iPhone prototype produced only three usability problems, but had a much more limited functionality compared to the iPad prototype.
Both prototypes were designed following heuristics proposed by Silva et al. (2015) and Watkins et al. (2014), specifically for apps for older people. However, both these sets of heuristics were developed from reviewing the literature rather than on empirical work with older people. It was clear from the comments made by participants and the usability
problems they encountered, that my interpretation of some of these heuristics lead to a prototype that was not suitable for this group of older people, who were quite typical of British people in their 60s and 70s living independently.
For example, the first heuristic proposed by Silva et al is “Focus on one task at a time instead of requiring the user to actively monitor two or more tasks, and clearly indicate the name and status of the task at all times” (H1). I followed this heuristic by only presenting one task per screen in the tablet version of app. However, a number of the problems in the category of “Excessive effort required by user to complete a task” related to only having one task per screen (9 problems encountered by 6 of the participants). Participants commented that they were losing their focus in using the prototype because the task was spread over too many screens and there were too many clicks to get through the screens to complete a task.
Another heuristic from Silva et al is “Give specific and clear instructions and make help and documentation available. Remember that it is better to prevent an error than to recover from it” (H7). Of the excessive effort problems, 10 problems (encountered by 7 participants) were related to the effort of reading too many instructions and messages.
These participants commented that they did not need so many instructions. In screens that required participants to read text or instructions on how to complete a task, they would just skim the text and not read them thoroughly. This is different from the conclusions from Hollinworth and Hwang (2009) that older adults need more instructions to successfully executive computer tasks.
These two issues mean that the majority of the 28 problems in the category of “Excessive effort required by user to complete a task” could have been avoided if I had put several tasks on a screen and cut down the amount of instructions. In fact, the older participants seemed very similar to younger users, they wanted to get on with things quickly, did not like having to navigate through a lot of screen with a lot of clicks and only skimmed through instructions.
To provide the fundamental task of adding and removing liquid intake, I followed the Silva et al. (2015) heuristic “Use simple and meaningful icons” (H33) and Watkins et al. (2014) heuristic “Use icons with symbols and text that clearly indicate the icon’s function” (R1)
(see Figure 4.11 in Section 4.6.2). I also labeled the buttons with verbs as recommend by Silva et al. “Make sure they are descriptive and use meaningful words and verbs when requiring an action”. However, all the problems (27 problems encountered by 16 participants) in the specific category of “Labels /instructions /icons on interactive elements not clear” related to this issue. Participants often commented that the labels and icons for the interactive elements were not obvious in their meaning and if the prototypes were to be in a real system, they would need to explore by try-and-error to figure out what each interactive element did.
In addition, there were two lessons learnt from this evaluation which did not relate to the heuristics used. Firstly I found that when choosing between a number of options, the older participants preferred buttons arranged top to bottom in a list form (see Figure 5.1(b)) than buttons arranged side-by-side (see Figure 5.1(a)). The readability of the labels on the buttons was clearer in a list form than side-by-side, and reading down a list may be more natural as the cognitive precursor to making a selection than reading the labels on an array of buttons.
Figure 5.1. From left. (a) The design of the buttons in the Home Screen, (b) The design of the buttons in the Main Screen
Secondly, one of the Interactivity categories of problems was “Concerns about how to proceed” where 14 participants encountered a total of 29 problems. Of these, 7 problems (encountered by 7 participants) were related to the use of the picker. Although the picker is a common input technique for touchscreen devices, the participants in the current study found the picker difficult to use. These participants commented that their physical abilities,
such as poor vision and hand tremor, caused them to have difficulties in controlling the picker.
5.4.1 Older adults design preferences and suggestions for MyDrinkApp
For the add liquid task, 11 (55%) of the participants preferred the mugs option (see Figure 4.13(c) in Section 4.6.2) because it is easier to visualize the amount of liquid they have consumed as compared to view the water bottle or the measurement jug. One participant commented:
I prefer the mugs option because we can know how much you drinking based on the number of mugs or so and we have more idea of what we’re drinking p2
Participants suggested showing the exact number of mugs to tally with the daily liquid recommendation, as exemplified in the following comment:
I recommend the number of cups should tally then with the recommendation earlier on it’s easier for us to think about it then p14
Participants also suggested simplifying the process to add a drink. They preferred as few steps as possible to complete the task. One of the participants commented:
I would say the design should be very simple with a few steps the simplest way is that you open it … it tells you the time have your images tap add and that’s it and you can do that in a couple of seconds as little as possible steps the better p18
Participants also suggested removing the features that allow users to update their liquid intake via inputting their own liquid volume rather than via the mugs, glasses, cups and tall glass options. They also suggested removing the feature to set own daily liquid recommendation, as exemplified in the following quotes:
can we simplify the add a drink features can you skip the part the user add own value here … I think by having 2 options will make the system too complicated p20
why not just stick to recommending the amount we suppose to drink water that's the purpose of this design isn’t p19
For reading tips, 16 participants (80%) preferred reading the tips screen by screen rather than reading the tips all in one screen. Participants commented that the amount of text to read in one screen can be tiring, boring and perhaps can lead to missing reading important tips. Some of the quotes by the participants include:
I prefer option 2 for the tips because scrolling can get bored with all those words p8
I prefer option 2 you might miss some important thing if you keep on scrolling p12