Garbage In, Garbage Out: Using Affordances

The trick is to make data-entry forms clear enough that workers understand what you require of them without having to ask. This understanding alone can drastically reduce the frequency of errors, but to turn that understanding into a payback, you'll have to design a label for each field that is truly obvious to the workers. Information designers call these clues "affordances", and if you're lucky enough to have technical writers or editors in your organization, you can probably enlist their aid in designing these clues.

Hart, Geoffrey J.S. Geoff-Hart.com (1999). Articles>Human Computer Interaction>Usability>Forms