myfood24 features
myfood24 contains two main areas: the researchers area where researchers can customise the website to fit their study design by adding project related text and logo, personalized additional help, a tailored invitation, send reminder emails to participants, select recall or diary option and select whether to display nutrient summary for participants or not. In the participants’ area, participants can select food items from the search bar or create a recipe in the ‘recipe builder’. Users can filter food items by selecting any of the filter options: ‘recently used items’, ‘recipes’ that have been entered previously and ‘food group’. For instance, if a search for ‘apple’ is made, only categories containing that item will be displayed, such as apple (fruit), apple pie (dessert), apple juice (drink), or by brand.
After the food item is chosen, food portion size (FPS) options are given as a dynamic extension of the search result screen to enable a seamless (all-in-one) user experience. There are various options presented to cover different food types and to maximize participants’ abilities to determine their portion size. myfood24 has images for 100 different food types (most frequently consumed foods), each food has 7 portion sizes to select from. To maximum image coverage, images are assigned to all food items that look similar. Food photos were obtained from the Young Person’s Food Atlas Secondary [31]. Moreover, participants can alternatively enter a specific weight in gram/ml if they know the exact portion size or use standard pack size.
The selected food item and its portion size are added to the meal tracker display area (breakfast, lunch, evening meal, snacks and drinks). To enhance the completeness of reporting, a pop-up message appears on the screen after selection of some common foods (e.g. bread, cereal) and probing for food items (e.g. butter or margarine; milk) that are often eaten in combination. Moreover, if participants forget to add the portion size after entering the food item, the software is programmed to prompt the participant to check the entry. Before submitting the dietary data the review screen prompts participants to check their entries and answer additional questions regarding supplement intake and whether or not their food record is typical for a regular day. After submitting the diary it can no longer be edited by users. A ‘thank you’ message with an optional summary of energy and eight nutrient intakes (energy, macronutrients, saturated-fat, fibre, sugar and salt) is displayed. For enquiries relating myfood24 use in research, please visit www.myfood24.org.
Usability-testing techniques
Figure 1 illustrates the study design which consists of two stages: stage-I was conducted in the beta-version of myfood24 and stage-II was conducted after making the amendments in the live-version of myfood24.
Participants
It has been reported that 80 % of usability problems are uncovered with inclusion of five participants and 90 % with ten participants with each additional participant contributing fewer new problems [19, 32]. Usability-testing of the beta-version therefore requires approximately 10 to 20 participants to enable the vast majority of usability issues to be identified [33]. In stage-II, more participants were recruited to test the acceptability and feasibility of using myfood24 (live-version) in a larger sample to ensure a representative sample of adolescents from each age group and gender. Adolescents aged 11–18 years old were recruited from four different secondary/high schools from different areas in Leeds. Participants who did not speak English as their first language were excluded, as myfood24 uses only the English language. Experience in using a computer was not required. Written consent was obtained from all participants and parental consent was obtained for adolescents who were younger than 16 years old. The study was reviewed and received approval from the University of Leeds Research Ethics Committee (MEEC 11–046).
Procedure
Stage-I: myfood24 (beta-version)
The researcher informed the participants in all stages that the study was not meant to test their ability to use the computer, rather it was to test the quality and attributes of myfood24. There were two different groups. In group-1, the researcher identified a list of key tasks that all users should be able to perform on myfood24. These pre-defined tasks were designed in a scenario to test specific features of myfood24; for example, using the ‘make a list’ function, entering food recipes and selecting different portion size options, as well as correcting mistakes (Additional file 1). The standardised tasks contained a variety of foods from the most commonly consumed foods by adolescents [34]. The test was carried out in a meeting room at the University of Leeds and lasted around 60 min for each participant.
Screen capture software (Camtasia Studio version 8 (Techsmith, USA)) was used to record participants’ screens and verbal recordings whilst undertaking the user tests of myfood24. During the session, users were instructed to speak out loud about positive and negative experiences as they performed each task, and they were encouraged to complete the tasks by themselves. The researcher observed the users indirectly (because some participants may have felt uncomfortable) and reported the users’ behaviour in light of the task analysis criteria (Additional file 1). At the end, the participants filled in a usability-acceptability questionnaire, and then received £5.00 remuneration.
In group-2, remote usability-testing [35] (participants completing the test at home) was carried out to obtain a clear indication of how myfood24 would perform in a real life situation and to test the availability of different food items in the software. Participants were un-moderated and asked to complete one 24 h dietary recall using myfood24. Then complete the usability-acceptability questionnaire that was used with group-1. Users were also asked to provide written comments on any problems they faced.
Stage-II: myfood24 (live-version)
Based on users’ feedback from usability-testing in stage-I, amendments were made to develop the final version of myfood24 (live-version). Seventy adolescents were recruited and divided into 14 groups, each group containing five-participants. This was based on logistical reasons in order to manage the research in schools. In each group, 3 participants were assigned to start with myfood24 and 2 were assigned with the interviewer (MPR) to reduce bias due to a learning process in the second set of responses. They were asked to report their 24 h dietary recall in myfood24 (without any assistance from the researcher) and then attend an interviewer-administered 24 h recall on the same day for two non-consecutive days at school. After the second use of myfood24 participants were asked to complete the usability-acceptability questionnaire.
Usability-acceptability questionnaire
The questionnaire consisted of three parts. The first part covering demographic information and questions regarding participants’ self-defined attitudes towards new technology. The second part contained three open-ended questions to comment on myfood24 (my favourite thing about myfood24 was…, my least favourite thing… and which particular areas users think we need to address in detail within the ‘Help’ section…). Finally, participants answered questions regarding myfoof24’s acceptability and satisfaction. This contained eight statements with a five-point Likert scale (1 strongly-disagree to 5 strongly-agree), in addition to the System Usability Scale (SUS) (Additional file 1) [36, 37]. SUS is a validated, reliable and free tool to use (34). There were two questions added to the previous questionnaire in stage-II. To identify adolescents’ opinions about myfood24 compared to the interviewer-administered 24 h recall, they were asked to rank the ease of undertaking each method using a five-point Likert scale (1 very-easy to 5 very-difficult), choose their preferred method and give the reason why.
Data analysis
In stage-I, qualitative data from the transcribed verbatim of the screen record for each participant and the researcher’s observational notes (group-1), as well as users’ comments regarding issues they experienced while using myfood24 (group-2), were analysed in accordance with the principles of thematic analysis [38]. The different codes were sorted into potential themes and all the coded data extracts were gathered within these themes. The themes covered the key areas of myfood24 and are presented in Table 2. All findings from group-1 and group-2 were combined to report the full range of usability issues and users’ recommendations to improve the tool. Findings from the open-ended questions in the questionnaire were analyzed using thematic analysis [38] and some typical quotes were selected to represent different views of users’ acceptability.
In order to reduce the risk of bias, all qualitative data were coded by two researchers and conflicts in coding decisions were reviewed by all researchers and resolved by consensus. Furthermore, the overall completion time in myfood24 was calculated in both stages. The overall SUS for each respondent was calculated for both stages. SUS is a 10 part statement that consists of a 5-point Likert scale for each part. For statements 1, 3, 5, 7 and 9 the contribution for each is the scale position minus 1. For statements 2, 4, 6, 8 and 10 the contribution for each is 5 minus the scale position. The sum of the scores is then multiplied by 2.5 to obtain the overall value. The overall SUS score ranged from 0 (negative-views) to 100 (positive-views) [37]. Moreover, findings from the eight statements of the Likert scale regarding myfood24 acceptability and user satisfaction were calculated before and after making the improvements and the overall median and interquartile range (IQR) were calculated. A Mann–Whitney U-test (two-sample) was used to test the rank differences in users’ perceptions between myfood24’s beta-version and live-version. Unpaired t test was used to test the improvement in the SUS in the 1st and 2nd stage. Analyses were performed using the STATA statistical software release 11 (Stata Corporation) and the significance level was set at 0.05.