Observers - Paper Prototyping: The Fast and Easy Way to Define and Refine User Interfaces - page 172

Weighing Risks and Rewards
Many activities, whether professional or personal, have both risks and rewards— investing in the stock
market, having a baby, and starting a business all come readily to mind. Intelligent people study the
inherent risks, seek ways to minimize them, and then weigh them against the rewards before making a
decision.
I'm a firm believer that it's okay to have observers sit in the same room with the users. This is how I
learned to conduct usability tests, and I've done it successfully hundreds of times. In my experience,
the benefits are considerable and the risks avoidable. Although I don't expect that everyone will agree
with me, I do hope that a better understanding of in-room observers will encourage others to try this
approach.
Thus far, the discussion of in-room observers applies equally to both paper prototyping and computer-
based usability tests. But with a paper prototype test, there are always going to be at least a couple
people in the room with the users, namely the Computer(s) and facilitator. Even if the observers will sit
elsewhere, I recommend that the Computer and facilitator understand the risks and benefits discussed
in this chapter. And given that paper prototyping is inherently a social activity, I don't believe that the
incremental risks associated with a few well-behaved observers are compelling enough to outweigh the
benefits that can be realized by face-to-face contact between those who develop interfaces and those
who use them.