ABSTRACT
Before you can begin to re-assemble the puzzle of human performance, you need data. What data do you need, and where do you get it? The first hunch is to say that you need everything you can get. Human factors, as a field of inquiry, often sits right at the center of an unfolding sequence of events. The people you investigate did not perform in a vacuum—they performed by touching almost every aspect of the system around them.
