What You Should Know About Prototypes for User Testing

Written by: Chris Farnum

There are several important factors to consider when you are planning to do prototyping for user testing. You will want to make careful choices about fidelity, level of interactivity and the medium of your prototype.

Degree of fidelity “An information architecture wireframe is NOT graphic design. I swear, it’s really not!!!”Fidelity is the degree of closeness to the “depth, breadth and finish of the intended product” (Hakim & Spitzer). Opinions vary a great deal on how much a prototype should resemble the final version of your design. Usability practitioners like Barbara Datz-Kauffold and Shawn Lawton Henry are champions for low fidelity —the sketchier the better! Meanwhile, Jack Hakim and Tom Spitzer advocate a medium- to high-fidelity approach that gives users a closer approximation of a finished version. You’ll want to make a decision about the right approach for you based on the needs of your project.

Low fidelity
You can use hand-drawn sketches to create a paper prototype. If you go this route, you may also want to help your users get into the spirit of things during the test by creating a complete low-fidelity, paper environment. This could include a cardboard box made to look like a computer and an object to hold to point and click with. These techniques help users to suspend their disbelief and get their imaginations involved so that they can better visualize the interface. The advantage of using rough sketches is that users will have an easier time suggesting changes. They may even grab a pen and start making their own changes (Datz-Kauffold and Henry).

In theory, low-fidelity sketches are also a time-saver, but this really depends on your point of view. Personally, I like to draw diagrams and wireframes in Visio where I can revise and move things around without erasing and redrawing. If you prefer to work this way too, and if time allows, you can always have those Visio drawings hand-traced or use them as a roadmap for making sketches to test with. You might even find a graphics tool with a filter that will convert a Visio-generated graphic into a hand-drawn sketch with wavy lines.

High fidelity
This approach takes you as close as possible to a true representation of the user interface —screen-quality graphics. All of the blanks on the page are filled in, and it looks good. However, you might not have all of the technical or backend problems worked out yet, or you might have only a small part of the entire site rendered. That’s why it’s still considered a prototype. For example, it might consist of a small series of Photoshop images or HTML pages with just enough functional links to convey the feel of the site’s flow. You may need to enlist the help of a graphic designer or web developer to build these in a reasonable amount of time. Advocates for high-fidelity prototypes argue that they are easier for users to understand just by looking at them. There is no disbelief to overcome, and it is easier to determine when they really do not understand the design. If you choose a high-fidelity prototype, make sure the you have enough of the design fleshed out so that users can complete several tasks. Decide on these tasks early, so you know which areas of the design need to be represented for your tests. Otherwise, you will be in for a great deal of preparation work.

Medium fidelity
In the grand tradition of Goldilocks, I find myself drawn to the middle approach. A medium-fidelity approach tends to include some visual design and a level of detail somewhere between high and low fidelity. Does this sound familiar? As an information architect, I’m accustomed to creating wireframes I can hand off to decision-makers, graphic designers, web developers and programmers. An information architecture wireframe is NOT graphic design. I swear, it’s really not!!! But… I’ll admit that it has enough visual design to convey a rough version of the user interface. Because I create these with drawing tool software, they tend to have more polish than hand-drawn diagrams. Hakim and Spencer are champions for medium-fidelity prototypes because they fit more seamlessly into the design process while providing more realism for users. I found this to be true during a project to design a search interface for Egreetings with my colleagues at Argus. I created rough draft wireframes for the prototype, and after testing I revised them for use in my deliverables.

Interactivity
Interactivity describes how your prototype behaves. Does your prototype react to user inputs with feedback? Can they “click” on something to go to another page or fill in a form? Will buttons appear to depress and drop-down menus work?

Static prototypes
Prototypes used for testing are static if they are pages or page elements shown to users, which don’t provide any feedback. It can sometimes work well to show a page to a user and ask them to explain it to you or to guess where they can go from here. In this kind of test, the user interprets the prototype rather than interacts with it. This is a good way to validate your design by checking to make sure users understand it. It’s also easy to score this sort of test when you have a standard list of questions to ask about each page.

Automated
Automated prototypes allow users to make choices that cause changes. The testing prototype provides the user with feedback. Elements are “clickable” and forms can be filled out. The interface reacts to the user while the tester observes. One way to do this is to create the prototype in HTML or some application that allows interactive elements such as Flash, Visual Basic or even PowerPoint.

Another way to achieve a kind of pseudo-automated interactivity when you have chosen a paper prototype is to pretend (Datz-Kauffold and Henry). Have you ever seen children at play pretend that they are driving a car by setting up chairs for the front and back seats, drawing a dashboard on a cardboard box, and using a Frisbee for the steering wheel? If you have set up the right environment for your users, you can ask them to pretend scraps of paper on a table are their computer screen. When they “click” on a drop-down menu by touching the element with a pointer, a tester assigned to the role of the computer provides feedback by swapping the closed menu for an open one that shows choices. The “computer” may need to write on some elements before showing them to the user, i.e., “Your search retrieved 523,621 hits.” It takes a few minutes to get test participants used to the idea, but if you encourage them to have fun with it you will learn a great deal. You can also easily try out different possible reactions to user input.

This method worked well during the Egreetings project. We especially emphasized the technique of asking the users to click and then provide feedback. We found it useful to laminate the screen components so we didn’t need to produce a clean copy of the test for every subject. The users could write on the laminated pieces with thin whiteboard markers when making selections and entering search criteria. Of course, this meant that we needed to take careful notes because of the need to erase between each test subject.

Here are some other tips to try for low-fidelity testing with simulated interactivity:

  • Bring extra paper so you or the respondent can sketch out an idea if the opportunity arises.
  • As with any user test, it really helps to ask the respondent to think aloud.
  • If you have the luxury, bring a team of three to the test: someone to take notes, someone to play the “computer” and another to facilitate.
  • Use a piece of posterboard as your “screen.”
  • Cut your design into separate pieces or zones as appropriate and ask the user to rearrange them in the order they prefer.
  • Attach the folder tabs that come with hanging files to components so they are easier to grab.
  • Invite users to throw away or cross out components that they don’t think are important.
  • Number the pieces so that you can easily refer to them in your notes and keep them organized.
  • If you do decide to bring separate copies of the test materials for each session, tape down the components to a larger piece of paper as arranged by each user so you have these artifacts to analyze later.

Prepare a kit for yourself containing:

  • Scissors and tape,
  • Different sizes and varieties of sticky notes (which make great drop-down menus),
  • Markers and pens in various colors and sizes,
  • Paper clips and binder clips for keeping slips of paper organized, and
  • Objects that the user can pretend are the mouse pointer, such as a feather or a small toy.

Medium
There are many possible combinations to choose from for building your prototype. One of the first choices to make is whether you want to have your prototype viewed on an actual computer screen or if you’ll be working on a tabletop with a paper prototype. Believe it or not, fidelity and interactivity are independent of the medium you choose. It’s probably most natural to think of the extreme cases. An automated HTML prototype is often high-fidelity and, of course, the medium is a computer screen. Likewise, a natural medium for a low-fidelity automated interactive prototype is hand-drawn sketches on paper. However, you can also have the following:

  • Low to medium-fidelity wireframes built in PowerPoint that show only lines and boxes with text;
  • animation features provide automated interactivity,
  • Static Photoshop prototype pages shown to users on a computer screen, or
  • Same as above, but printed out in color on paper.

Mixing the variables
You can mix these three variables (fidelity, interactivity and medium) in many different combinations. The exact combination you choose should match the goals you determine for your testing. Possible goals for an IA prototype include:

  • Testing the effectiveness of labels and icons.
  • Finding out the right balance of depth and breadth of a topical hierarchy.
  • Determining the right options to offer for narrowing a search.
  • Choosing the most important metadata elements to show on a search results screen.
  • Settling the question of whether your target audience accomplishes tasks better with a task-oriented organization scheme or with a topical organization scheme.

If you live and breathe NetObjects Fusion and don’t have much time, your preference might be to create a medium-fidelity prototype. That way you could test that sitemap you are working on using some rough placeholder graphics or text instead of the finished graphic design. How you mix the variables depends on the time and budget you have available, as well as your work style. Try experimenting with different approaches to learn how prototyping will work best with your design process.

For more information

  • Evaluating Information Architecture,” Steve Toub (2000).
    http://argus-acia.com/white_papers/evaluating_ia.html
  • UPA 2000 Proceedings:
    #28 – “Waving Magic Wands: Interaction Techniques to Improve Usability Testing Low-Fidelity Protoypes,” Barb Datz-Kauffold & Shawn Lawton Henry.
    #32 – “Prototyping for Usability,” Jack Hakim & Tom Spencer.
  • “Prototyping for Tiny Fingers,” Marc Rettig, Communications of the ACM, Vol.37, No.4 (April 1994).
    http://portal.acm.org/citation.cfm?id=175288 (ACM Membership required)
  • Using Paper Prototypes to Manage Risk,” User Interface Engineering.
    http://world.std.com/~uieweb/paper.htm
Chris Farnum is an information architect with over four years’ experience, and is currently with Compuware Corporation. Three of those years were spent at Argus Associates working with Lou Rosenfeld and Peter Morville, the authors of Information Architecture for the World Wide Web.