People are fuzzy around the edges, and so is their behaviour.
Users aren’t a very reliable source of hard data. They have ideas, but often no more than one or two. They have needs but may not know what they are. They think they know what they want, but they probably don’t. And they can rarely imagine things that don’t yet exist.
“If I had asked people what they wanted,” said Ford, “they would have said faster horses.”
They are a good source of soft data, however – although gathering soft data from fuzzy humans requires more indirect methods: observing them in their natural habitats, empathizing with their worldviews, and asking indirect questions – including why a lot – to get to the root of the problem we want to solve.
Taking into account the human factor is an integral part of design research: you have to frame the question correctly to get to the right answer. Building a better mousetrap won’t help if the mice have started a colony in the basement.