There's an old adage that 90 percent of filmmaking is in the casting. Throughout the process of making a movie, doing the work up-front to get the right performers pays off and ultimately leads to a superior result. We've found this adage also proves true when we're conducting user research, because the quality of the results comes from selecting the right users at the project's outset.
So true – sometimes we're so adamant about practicing user centred design methods that we get just anyone involved, instead of truly representative users, just so we can say we did user research or usability testing. Or maybe you're in a situation like this: yesterday someone suggested I use people from the project team. And that can be worse than no users at all.