Formal reports are the most common way of documenting usability studies, but according to Jakob Nielsen informal reports are faster to produce and are often a better choice.

"You can maximize user interface quality by conducting many rounds of testing as part of an iterative design process. To move rapidly and conduct the most tests within a given time frame and budget, informal reports are the best option."

Links:

• The article Formal Usability Reports vs. Quick Findings 

Henrik Olsen - April 25, 2005

See also: Usability testing (68)