Writing with Authority
http://inkjuice.com/?p=36

Bristow, Gemma
Inkjuice
2008

Abstract:

Technical writers write with authority. That’s the job: to present the subject with authority, so the reader will feel confident about the accuracy of the information or confident about using the software. There’s no place for hedging. You write, ‘Press the OK button’. You don’t write, ‘Press the OK button – I think.'