I was talking to the people who did human-factors testing of documentation. They would get 'subjects' completely unfamiliar with the product and film them interacting with the computer. The idea was to make sure the documentation was not making unwarranted assumptions.
The user had problems getting the computer to do anything. The instruction step said "Put the mouse pointer on the icon and click." Nothing ever happened. Upon watching the video recording they saw that the subject interpreted the word 'on' to mean 'on top of', as in 'just above'. They would never have caught that without seeing it happen.
The wording was improved.
Biting the hand that feeds IT
