Mobile Evaluation Log ===================== Evaluator: Otto Age Range : 40-49 Gender: male Profession: Professor Research Fields: HCI and Visualization Years of Experience: 25 Device: HP Elitebook 840 G10 OS and Version: Debian 13 Screen Size: 27" Screen Resolution: 3840 x 2160 Web Browser: Chromium 141.0.7390.107 Ad Blocker: none Internet Connection: none Screen Recording Software: OBS Studio 32.0.1 Recording Resolution: 1920 x 1080 Date of Evaluation: 2025-09-30 Negative Findings (Problems) ----------------- o OT-Neg01 Title: Line is hard to catch Description: Polyline selection in the Chart is an important tool. The line can only be selected when directly clicking on it. Video Clip: ot-neg01-keywords.mp4 Heuristic: A07 Flexibility and Efficiency of User How Reproducible?: Go to any Chart → select a line o OT-Neg02 Title: Tooltips on Actions Description: The web application has no indications for dragging, filtering, or inverting. Tooltips are often used in modern applications. Video Clip: ot-neg02-tooltips.mp4 Heuristic: A06 Recognition Rather Than Recall How Reproducible?: Scroll down until the first Chart is displayed → hover over an arrow/triangle shape/label o OT-Neg03 Title: Reset Table and redraw Chart Description: The "Reset Table" button should only be used to reset the table and not to redraw the chart. The "Redraw Chart" should be to redraw the chart. Video Clip: ot-neg03-redraw.mp4 Heuristic: A04 Consistency How Reproducible?: Scroll down to the table → click on the "Reset Table" button o OT-Neg04 Title: Data Values Description: When hovering/selecting a line in the chart, the user expects to see the values. Video Clip: ot-neg04-values.mp4 Heuristic: A06 Recognition Rather Than Recall How Reproducible?: Scroll to any Chart → hover over/select a line o OT-Neg05 Title: Scrollytelling Animations Description: The explanation on how to interact with the system could be changed to a more interactive approach. (Scrollytelling)Animations to explain Interactions with a system feel more natural to users as more websites started to integrate this feature. Video Clip: ot-neg05-animations.mp4 Heuristic: A02 Speak the Users' Language How Reproducible?: Scroll to Interactive Operations o OT-Neg06 Title: Interaction late Description: The interactions in the system partially appear after the explanation. This breaks the thinking process of the user. Video Clip: ot-neg06-interaction.mp4 o OT-Neg07 Title: Embed Symbols in Text Description: How to use the chart is explained in written Form. Symbols could be placed into the text to recognize them faster. Video Clip: ot-neg07-embed.mp4 Heuristic: A10 Help and Documentation How Reproducible?: Scroll to "Operations on Dimensions" o OT-Neg08 Title: Open Context Window Description: The user expected that the context window could be opened at any position on a dimension. The explanation should make clear when and where the context menu can be opened. Video Clip: ot-neg08-context-window.mp4 Heuristic: A10 Help and Documentation o OT-Neg09 Title: State of Chart Description: The user can be confused by the current state of the chart. The application should put important information in front of the user. Video Clip: ot-neg09-state.mp4 Heuristic: A10 Help and Documentation How Reproducible?: Scroll to any Chart o OT-Neg10 Title: Out of range data points Description: Out-of-range datapoints have to be remembered by the user. To make it visible to the user that a specific range is set, unused data points could be collected beneath the chart. Video Clip: ot-neg10-range.mp4 Heuristic: A10 Help and Documentation How Reproducible?: Scroll to any Chart o OT-Neg11 Title: Reversible Table Description: It is not possible for the user to undo or redo a single action in the "Personal Finance" Table. The user can only get back to the initial state. Video Clip: ot-neg11-undo.mp4 Heuristic: A03 Reversible Actions How Reproducible?: Scroll to "Personal Finance" Table o OT-Neg12 Title: Separate States Description: It is not always clear to the user which chart an explanation belongs to. This is especially so when a chart change happens. Video Clip: ot-neg12-state.mp4 Heuristic: A08 Aesthetic and Minimalist Design How Reproducible?: Scroll until the Chart switches o OT-Neg13 Title: Coordinated Multiple Views Description: The screenshot in the section "Coordinated Multiple Views" does not fit in with the rest of the application. Video Clip: ot-neg13-coordinated-multiple-views.mp4 Heuristic: A04 Consistency How Reproducible?: Scroll Down to "Coordinated Multiple Views" o OT-Neg14 Title: Separate Introduction and Interactivity Description: For the user, it can be confusing to have an explanatory Text mixed with interactive actions. In the application, the Explanation is mostly separate from the Interaction. Video Clip: ot-neg14-interactivity.mp4 Heuristic: A04 Consistency How Reproducible?: Scroll Down to "Case Study" o OT-Neg15 Title: Interact Directly Description: The application wants to explain to the user how the system works before giving full control. With the Interact Directly button, this does not hold up anymore. Video Clip: ot-neg15-interact-directly.mp4 Heuristic: A04 Consistency How Reproducible?: Scroll Down to "Case Study" o OT-Neg16 Title: Simple Colors Description: Different shades of the same color are used. An existing color palette could be used for more familiarity. Video Clip: ot-neg16-colors.mp4 Heuristic: A04 Consistency How Reproducible?: Scroll Down to "Looking for Correlations between Dimensions" o OT-Neg17 Title: Handmade Icons Description: The icons used in the Double Arrow Menu deviate from standards. A standard icon library is used in other web applications to solve this problem. Video Clip: ot-neg17-icons.mp4 Heuristic: A04 Consistency How Reproducible?: Scroll to any Chart → click on the button with two arrows on the left-hand side o OT-Neg18 Title: Arrow Menu hard to find Description: When seeing a chart, there is always a Menu-Button with two arrows on the top left side. Such a menu is not a standard in such applications and can be hard to find. Video Clip: ot-neg18-menu.mp4 Heuristic: A02 Speak the Users' Language How Reproducible?: Scroll to any Chart → click on the button with two arrows on the left-hand side o OT-Neg19 Title: Button Names Description: Icon buttons are used for predefined, clear actions that are often used. In the Double Arrow Menu, the buttons are not visible all the time. Video Clip: ot-neg19-buttons.mp4 Heuristic: A02 Speak the Users' Language How Reproducible?: Scroll to any Chart → click on the button with two arrows on the left-hand side o OT-Neg20 Title: Range on first chart Description: The range setting on the first chart does not work as the user intended. The maximum has to be bigger than the actual maximum, which is not clearly explained to the user. Video Clip: ot-neg20-range.mp4 Heuristic: A10 Help and Documentation How Reproducible?: Scroll down to first graph → Right-click on "Leftover" → click on "Set Range" → enter 2900 as Minimum → click "Save" Positive Findings ----------------- o OT-Pos01 Title: Context Menu Description: Context Menus can be great for many users. Video Clip: ot-pos01-context-menu.mp4 How Reproducible?: Scroll to any Chart → Right-click on the label of a Dimension o OT-Pos02 Title: Adjusting the Dimension's Range Description: Adjusting the Dimension's Range is not commonly implemented. It is a very useful feature. Video Clip: ot-pos02-range.mp4 How Reproducible?: Scroll down to "Operations on Dimensions" o OT-Pos03 Title: Case Study Description: The Case Study lets the user step through different actions on Parallel Coordinates. It is an interactive explanation of possible steps that can be taken to analyze the data. Furthermore, it is a great tool for teaching as the user can get to see the steps as they are taken. Video Clip: ot-pos03-interactivity.mp4 How Reproducible?: Scroll to "Case Study" Bug Findings ----------------- o OT-Bug01 Title: Animation is wrong Description: The animation on the Heart Health Dataset when clicking Move Fitness Score Dimension is wrong. The Bug is just the Animation. Video Clip: ot-bug01-animation.mp4 How Reproducible?: Scroll down to "Usage" - Example of a Negative Correlation → click on "Move Fitness Score Dimension" o OT-Bug02 Title: Case study backwards freeze Description: When the user changes something with the Interact Directly button between Steps, the backward functionality can be broken. Video Clip: ot-bug02-freeze.mp4 How Reproducible?: Scroll down to "Case Study" → move a step → click on "Interact Directly" → change something in the chart → click on "Step Through" → try to step back