# Consumer-Driven Usability Test of Mobile Application for Tea Recommendation Service
## 3 Methods  
### Development of TeaPick\({}^{TM}\) Mobile Application  
Our application provides useful information on blended tea and recommends tea suited to the preference of users. To build our recommendation logic, we adopt a content-based recommendation approach among other existing approaches as the first step towards the tea recommendation service. Collaborative filtering, which is another representative method used for recommendation systems based on the similarity between users, requires the user rating or preference information from a large number of users. However, it is difficult to apply this approach at the current stage since there is no available user preference/rating database for various blended teas. Based on this study, it will be possible to further develop a new tea recommendation service that utilizes the collaborative filtering method or hybrid one. For content-based recommendation, it is necessary to determine product attributes and calculate user's preference for products, and to determine rankings of products accordingly. To ensure effective recommendation, it is important to determine what the main attributes of the products are and how to express the user's preference for them. Blended tea can be represented by a variety of attributes such as flavor, health benefits, recommended drinking time, presence of caffeine, strength of flavor, and ingredients. However, in blended tea selection, not all attributes are considered equally, but their importance differs for each attribute. Moreover, it is rather complicated to consider all of these various attributes to create a user's preference profile. We collaborate with four domain experts to select the key attributes of the blended tea and develop a database for blended tea. The four experts consist of one tea sommelier (13 years of experience), two tea manufacturing experts (8 and 21 years of experience, respectively), and one food and nutrition expert (22 years of experience). The attributes of blended tea selected through our collaboration with the tea experts include flavor, health benefits, recommended drinking time, two main ingredients, and presence of caffeine. Among them, flavor and health benefits include a total of 9 factors, respectively. Recommended drinking time includes a total of 5 factors. For this purpose, we first started with popular blended teas of one tea brand (i.e., 34 teas) since there are tens of thousands of different blended teas available in the Korean market. We collected information about the flavor, health benefits, and recommended drinking time of those teas from the experts through a couple of rounds of surveys and interviews. To achieve a common conclusion from the collected information, we adopted the Delphi method and determined the factors accordingly. To represent the unique characteristics of each tea, the four abovementioned experts assigned a score from 1 to 5 for each factor of flavor and health benefits. To develop a prototype of _TeaPick\({}^{TM}\)_ for our experiment, we target 18 commercial blended teas and build a tea attribute database for those teas. Table 1 shows an example of the current tea attribute database. In order to create a user's preference profile, it is important to determine the tea attributes which users need to specify their preferences for. It is also important to present the appropriate number of attributes that the user can intuitively select and enter on the mobile screen. For this purpose, we conducted an online survey to determine the key attributes of tea and their importance to generate the desirable user's preference profile. The survey respondents were 462 male and female adults, aged 19-59, living in six major cities in Korea. We examined the importance of health benefits, flavor, and drinking time. The results show that the most important factor in selecting blended tea was flavor, followed by health benefits. We thus assign a higher weight to the flavor than to other factors.