1. Low Fidelity Prototyping and Wizard of Oz Studies Because they are easy to create and modify, low fidelity prototypes commonly provide designers with valuable feedback on user interface designs. They are often used within the context of wizard of oz studies, in which a human wizard simulates the interface as test users interact with it. User interface designers typically construct low fidelity prototypes with various tools: Christopher D. Hundhausen, Anzor Balkar, Mohamed Nuur, and Stephen Trent Visualization and End User Programming Lab School of Electrical Engineering and Computer Science Washington State University Pullman, WA {hundhaus, abalkar, mnuur, This research is funded by a Hewlett Packard “Technology for Teaching” grant (no. U06TFH0033E) 3. WOZ Pro Design Through an iterative, user-centered design process, we have developed WOZ Pro (Wizard of OZ Prototyper), a pen-based software environment that supports the quick and easy creation and testing of low fidelity user interface prototypes. With WOZ Pro, constructing a low fidelity prototype and running a wizard of oz study are as easy as 1-2-3: 2. Problems with Existing Low Fi Prototyping Tools 1. Design change propagation is cumbersome. With art supplies, making changes to multiple screens requires repetitive erasing and redrawing. With computer-based tools, it may be difficult to apply changes to a specific subset of screens. 2. Running wizard of oz studies incurs a potentially high cognitive load. Low fidelity prototypes can grow to dozens, even hundreds, of screens, making it difficult for human wizards to quickly navigate from screen to screen. If one is willing to put in implementation effort up-front, tools like SILK and DENIM can eliminate the need for a human wizard—and hence do not technically support wizard of oz studies. simple art supplies (e.g., pen, paper, and scissors) general-purpose graphics and presentation software (e.g., PowerPoint®, Photoshop®) Pen-based low fidelity prototyping software (e.g., SILK, DENIM; see 5. Future Work In order to better support wizard of oz studies, we will explore such a task pile metaphor in future versions of WOZ Pro. 1.Low Fidelity Prototyping and Wizard of Oz Studies 4. Empirical Evaluation In order to evaluate the effectiveness of WOZ Pro, we recently ran an experiment in which 24 participants used either WOZ Pro or pen-and- paper to construct and simulate, in wizard of oz fashion, a low fidelity prototype of a 21-screen website. We are presently analyzing video data to obtain four dependent measures: 1. Time to construct prototype 2. Accuracy of constructed prototype 3. Average delay between screen transitions 4. Average number of screen transition errors Pen-and-paper participant sketches screen WOZ Pro participant sketches screen In our experiment, WOZ Pro participants often created large, cluttered STNs that were difficult to work with. In contrast, pen-and-paper participants simply organized their screens into piles according to task. 2.Problems with Existing Low Fi Prototyping Tools 3. Present prototype, in wizard of oz fashion, to test users in “Run Screens” mode. Pop-up navigation menu constrains valid next screens according to STN defined in (2) 2. Specify state-transition network (STN) in “Edit Screen Transitions” mode. Drag-and-drop screens from “Unlinked Screens” pane onto canvas; link screens via drag and drop 1. Create a low fidelity prototype by sketching screens in “Design Screens” mode. A toolbox of sketching tools appear on left; screen thumbnails appear on right WOZ Pro supports a novel feature that allows the designer to propagate a series of recent edits to an arbitrary subset of screens. Here, we have changed the “Caffeine” menu item to “Smoothies” (see “Preview” pane), and we are about to propagate that change to all screens.