Finding the Right Users
http://www.adaptivepath.com/publications/essays/archives/000102.php

Merholz, Peter
Adaptive Path
2003

Abstract:

If you’re using the eenie meenie method to select users for your research, perhaps it’s time you tried something a little more scientific. There is no such thing as sound user research without an airtight user-selection process behind it. No matter how good the observation and analysis, it’s all for naught if you’ve studied the wrong people. Too much “user research” is conducted, analyzed, and applied without anyone ever having spoken to users. Researchers then offer guidelines based on the needs and preferences of people who would never use the product in question. Relevant user research results depend on two factors: First, obviously, you’ll need to find people who are likely to use the product. Second, you’ll need to interview enough of them so that trends emerge from their collective behavior. These trends will indicate your primary design targets.