Heuristic Evaluation, “Tree Tap” Application

Team Gogglefox

Brandon S. Perelman

Team Website

Team Cognitive Walkthrough

Application Description

Gogglefox’s “Tree Tap” is an application for smart phones running the Android operating system intended to encourage a citizen science partnership between amateur maple syrup enthusiasts and the US Department of Agriculture. Tree Tap provides a database for maple syrup producers, allowing them to log tree species and diameter, taps (type and number), and yield. Once they have collected this information, enthusiasts can compare these factors or examine them against environmental factors such as temperature. Once the data is logged, it is accessible by users and the scientist stakeholders. The app is expected to foster social networking by allowing users to compare their progress with those of friends.

UI Domain

Tree Tap belongs to the UI domain mobile hobbydatabases, but it should be noted the application also includes tools, such as a circumference to diameter calculator. Examples of mobile databases for hobbyists include BeerSmith, an application for amateur brewers that includes recipes and tools for calculating beer recipes, and the iPhone application iBird, an application for bird watching enthusiasts. While these mobile databases serve a practical purpose in that they allow the hobbyist to track and log hobby-related information to increase performance in the hobby, they also enhance the experience, allowing the user to interact with the hobby, via the application, even when they are not directly engaging in the hobby. Therefore, they can be thought to extend the breadth of situations in which an enthusiast can engage in a hobby.

Heuristic Usability Principles

  1. Practicality: Does the app serve a practical function for the user beyond participation in citizen science?
  1. Simplicity: Our users will not likely be experts in using smart phones.
  1. Supporting the Hobby: The design should increase the extent to which users enjoy the hobby, and/or the user’s ability to skillfully practice the hobby.
  1. Engaging: We want the users to be excited to use the app.
  1. Parsimonious: The app should aim to deliver the maximum amount of information in the simplest way possible.
  1. Responsivity: The app should clearly display feedback for the user’s actions.
  1. Easy Interaction: Buttons and text should be sufficiently large as to support the older target demographic. Buttons should be both easy to see and easy to press. Text should be large enough to read easily.
  1. Robustness: The app should funnel users to the proper choices, be safe to use, and incorporate features that discourage failure.
  1. Intuitive: Recognition versus recall – users should not be confused when first using the app.
  1. Tutorial and Help: The app should incorporate “hand-holding” that is repeatable and easily accessible.

Potential Usability Problems and Critical Usability Concerns

  1. * Home screen contains many options, the differences between which are not readily apparent. For example, how is “Tap” any different than “Enter data?” What does “References” mean? These problems violate the Simplicityand Robustness principles, and make the design counter-Intuitive.
  2. The complicated and ambiguous home screen is a critical concern because there are buttons that are seemingly redundant but accomplish different tasks. The primary users are not smart phone experts, and so must be guided to the correct choices. For example, a user downloads the app and wants to enter existing data from his log book. He clicks on Enter Data, which presumably generates a failure since he has not yet entered any trees using the Tap button.
  3. Back buttons depict the arrow pointing in the wrong direction, violating the Intuitive principle.
  4. The Tap Entry screen contains fields for both circumference and diameter. These may lead the user to believe that they are intended to record both. Considering that there is a calculator in the Tools section, it seems that there are three fields or areas that could be easily handled by a conversion clicker next to the field. This violates the Parsimonious principle by introducing unnecessary complexity, and Practicality as it does not provide functionality to the user.
  5. The Tap EntryScreen’s Sap Yield field does not list any measurement units. Since amateurs may not have any a priori assumptions regarding the appropriate measurement units, the app should guide them using domain-standard measures. This violates the principle of Supporting the Hobby.
  6. The two problems listed above are critical usability concerns because they cause serious problems not only for the user, but also for scientists who will use the data. For example, suppose that two different users are logging their sap yield using the app. One user is a big time producer, and logs his daily sap yield in gallons. Another user is a very small producer, and logs his daily sap yield in ounces. If both users enter the same value, to the scientists it will appear as if they are producing the same amount of syrup. We cannot rely on the user to specify the unit of measurement, and should provide them with guidance.
  7. The Tap Entry Screen does not include any provision for detailing different styles of taps, or sizes. This violates the principle of Supporting the Hobby.
  8. The Help Screen’s “Guide” button is vague. Is this intended to be a guide to different types of trees? Taps? General knowledge, or something pertaining to the app? This violates the Tutorial and Help principle.
  9. The Tools Screen includes a weather tab, and it is not clear how this differs from the weather display on the home screen. This violates the Parsimonious principle.
  10. The Records Screen is very complicated includes some rather small typeface. There may be easier ways to display this data. This violates the principles of Easy Interaction, Simplicity, and Parsimonious. It is also not clearly how the user would change to previous months. If the user cannot use this information, we will not see Engagement.
  11. The records screen is a critical usability concern because, if it does not work for the user, the user will have no interest in engaging with the app. For example, an older (60’s) amateur maple syrup producer is rather influential in local hobby clubs, and produces relatively high yield. However, because he is unable to understand and work with the records screen, he loses face and decides to abandon the app in favor of his old notebook.
  12. Generally, the user is not informed of how often they should input data. This violates the principle of Supporting the Hobby.
  13. Generally, as the users are not professionals, they may need to access Help from any screen. Perhaps there should be a question mark button on every screen that allows the user to access screen-specific help. This violates the Tutorial and Help principle.
  14. Since Help is accessible only from the main screen, the user must navigate back to the main screen in order to access help. This may create issues with saving data. For example, suppose that a user enters data in the Tap Entry screen, but then has a question about tree type. He presses the back button and navigates to the help screen and finds the answer to his question. When he returns to Tap Entry screen, he finds that his data has been erased because he did not press Save before navigating back to find Help.