# Consumer-Driven Usability Test of Mobile Application for Tea Recommendation Service
## 3 Methods
### Experiment Setup  
We conducted a user study based on survey questionnaires to evaluate our prototype application to recommend blended tea, _TeaPickTM_. Our evaluation consists of two tests: the application usability test of _TeaPickTM_ and the consumer acceptability test for recommended tea. The former was designed to evaluate the usability, usefulness, satisfaction, intention to use, and brand attitude regarding the application and recommendation results after using _TeaPickTM_. The latter was designed to evaluate the overall preference for the recommended tea after the participants sampled the tea. **Participants**: We recruited 33 participants for our experiment. After the experiment, we excluded two of them since their responses were incomplete. As a result, we analyzed data from total 31 participants. They included 17 males and 14 females and their age range was between 21 and 34 (mean: 25.3, SD: 2.82). Most of them were undergraduate/graduate students and some were office workers. This study was conducted in accordance with Institutional Review Board of KOREATECH (18120411). We gave the participants a brief explanation about the study purpose and obtained their consent. Everyone voluntarily participated and was compensated with a meal coupon worth USD 5. **Surveys**: The survey questionnaires consisted of two types: one for the app usability test (type A) and the other for evaluating preference of recommended tea (type B). The type A questionnaire was designed with 5 constructs. These were the usability of the _TeaPickTM_ mobile application, the perceived usefulness of the application, the satisfaction with recommendation, the intention to use the application, and the attitude toward recommended tea brands (i.e., brand attitude). We included 5 questions per construct based on the previous research [24; 27; 28; 29]. The type B questionnaire was designed to evaluate the overall acceptability after users had sampled the recommended tea. Both types of questionnaires contained 7-point Likert scale questions (1 means strongly disagree and 7 means strongly agree). **Procedure**: The experiment consisted of three parts. First, we briefly explained the purpose of the study and the process of experiment. We then provided the participants with an Android tablet on  
Figure 1: Example screenshots of _TeaPickTM_ prototype application. (**a**) A screen for starting recommendation, (**b**) A screen for user preference input, (**c**) A screen for recommended teas. * The current prototype is built in Korean for user study. which the _TeaPickTM_ application was installed. Second, the participants freely used the application while the experimenters observed how they used it and measured the total time they spent using it, meaning the time from when they touched the application launcher icon until they said that they were finished running the application. We allowed them to ask questions when they experienced any difficulty using the application. After they finished using the application, they responded to the type A questionnaire. In the meantime, the experimenters prepared the samples of three recommended teas. Third, the participants tasted those tea samples and responded to the type B questionnaire. To ensure that the experiment ran smoothly, we used Android tablets (Galaxy Tab S3, Samsung Electronics Co., Ltd., Suwon, Korea) instead of allowing the participants to use their smartphones. Also, we set up a tablet on a cradle (BANADA(SS1 Stand, DMK Korea Co., Ltd., Bucheon, Korea) so that the participants could use it stably. We used two tablets to allow two people to participate in the experiment simultaneously. **Sample tea preparation**: To prepare the tea samples, we purchased 18 tea products used to implement the prototype of _TeaPickTM_. Among the commercial blended tea brands, we selected one brand (LOOKOUTEA, RESH Corp., Seongnam, Korea) to avoid any differences based on the brand. We prepared sample teas following the instruction to make tea shown in the package of tea products.