Which organizations and how to classifies hotels by the number of stars?

Answer 1

Many organizations rate or classify hotels, Zagat, AAA, Orbitz, Expedia, HotelTravelCheck.com, J D Power. There is no consensus some have 5 star ratings or only 4 star ratings or even in Asis there is a 6 star rating.

http://en.wikipedia.org/wiki/Five_star_hotel

Wikipedia has an explanation and confirms that there is no one consensus rating organization. Country to country and really no standard