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What is, how it works
Paper prototypes are a tool that allows to test the efficiency of interfaces meant for human interaction (more commonly software or website related interfaces) at a very early stage of their design phase. In this way they are quite useful in Risk and Quality Management for they help assure that the final product will have high usability standards.
Right after finding the initial ideas for the design layout of an interface it is possible and advisable to run user tests to find out how efficient that design would be with human interaction and to correct structural details, before committing deeper into the design development. For this first visualization it is best to use just rough sketches of the design (laid out on paper) that allow to test its mechanics, rather than a more elaborate prototype (software based) since visual styles and general appearance details are not yet to be discussed. The point of paper prototyping is not to sell the “look and feel” of a design, but rather to test its mechanics and usability – in a fast, reliable and quite cheap way.
If we take as an example a website, the paper prototype is built by sketching the contents of each webpage and corresponding links into a plain sheet of paper in a way that the paper pages reproduce the basic layout of the contents and controls that the user would see on the computer screen. This is done very roughly: hand sketching with coloured pens, cutting and gluing different pieces of paper are the most common techniques used. Possible pop-up or drop down menus are also made by cutting smaller pieces of paper.
Prototyping in paper is a good way to involve the whole project team in the early stage of the design process, since everyone can master the cut-and-glue technique (as opposite to html or flash prototyping) and all can do it together at the same time, exchanging views and ideas. Building of a complete website paper prototype can be done in just a few hours. Evaluating the usability of that design begins right after.
The testing team will consist of about 4 people, who will take different roles as the test proceeds:
- The facilitator: this person will be the only one talking to the user and conducting the user test.
- The “computer”: this person will operate the paper model simulating that it behaves as a real computer.
- The observer: this person will take notes on the user behaviour. There may be several observers.
- The camera: this person will film the test so that the development team can later analyse it and draw some conclusions.
To begin the test they should ask the users to perform some tasks on the paper model of the website, as if they were using a real computer. When the user is done with all the tasks (successfully or not) the test team should interview the user, gathering further impressions and comments on the tested interface.
The results of each testing session can be used to improve the model for the next one, since paper prototypes are quite easy to modify. Corrections can even be made as the test is proceeding if it’s needed. By the end of the test sessions the test team will have gathered a lot of useful information to improve the design further. Paper testing can be done again in later stages of the design.
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Possible general uses
- Design an interface from scratch
- Redesign an interface or part of an interface that exists already.
- Applications for personal computers
- Webpages
- Mobile phones
- Digital cameras
- Ticket selling machines
- GPS devices
- ATMs
Example of concrete usage
I have used a paper prototype as an academic exercise. I was part of a team designing a website which had wiki-style characteristics, such as collaborative writing and editing of texts documents, comment posting, link posting, search and print functionalities, as well as registration and login requirements. These were the main features of the website design that we would like to test.
So, our starting point was creating a flow chart defining the number of pages needed and what information, contents and functionalities should be in each one of them. Following that we built a paper prototype from that structure, using the traditional coloured pens, sticky paper, scissors and glue.
We made one first usability test ourselves and we corrected some features of the prototype immediately after, like:
- Adding a warning sign for a non-existing page;
- Adding some content for title boxes so they would be closer to real contents.
After that first round we started testing with real users. We had a team of 4 testers, which included one person for filming, one to act as the computer, one to take notes and another one to lead the interview.
The following are some of the changes to our design that emerged as necessary from this user testing:
- Need to reposition or resize the “Create a New Document” button, reducing its visual impact – it is drawing too much attention right now.
- Highlight or even rename the “News-Media” box – maybe to a more obvious title like “Links to External Information”
- Change the name of the button “Page History” to “Document History”
- Add an error message in case people try to post a comment without actually typing anything in the comment box
- Add a “Links to External Information” box also on the documents page
References
Articles
Klee, M. 2000. Five paper prototyping tips.
Available from User Interface Engineering.
Rettig, M. 1994. Prototyping for tiny fingers.
Communications of the ACM (April). 37(4):21-27.
Snyder, C. 1996. Using paper prototypes to manage risk.
Available from User Interface Engineering.
Websites
Paper Prototypes
http://www.paperprototyping.com/
User Interface Engineering
http://www.uie.com/
