John Brooke came out with this "quick and dirty" usability test for real life application in his work place and it has been hugely successful since. I will use the usability scale on my Enthuasastep prototype for the smart phone.
- For odd items: subtract one from the user response.
- For even-numbered items: subtract the user responses from 5
- This scales all values from 0 to 4 (with four being the most positive response).
- Add up the converted responses for each user and multiply that total by 2.5. This converts the range of possible values from 0 to 100 instead of from 0 to 40.