The SUPR-Q is a 13 question standardized questionnaire which generates a normalized score. The scoring system is based on the relative ranking from a database of over 100 websites and thousands of users.
The SUPR score is made up of a global score which is a percentile ranking based on four factors: Usability, Trust & Credibility, Appearance, Loyalty
In addition you get percentile ranks for each factor so you can see the strengths and weakness by factor. The SUPR-Q was developed through a process of psychometric validation. Over 75 candidate questions were tested on thousands of users across hundreds of websites to arrive at the 13 which provide the most reliable, sensitive and valid picture of the attitudes which shape the success of a website.