Joined: 01 Jan 10
16 Nov 11 4:31 pm
I am not sure this will answer your question.
I use SEO QUAKE to determine PR of a page that I am on. A website becomes an authority site when it has grown to the level that the information contained within the site is all-inclusive. Meaning the site information is able to answer multiple questions the site user customarily has when researching that particular niche. The page rank given by Google indicates that Google has developed confidence in that specific page.
I do not know of any software or analytics site that ranks authority levels. However the PR rank is calculated on a wide variety of components. A site that has become an authority in their niche will display many of the components that Google rates to determine page rank.
I hope this information is helpful.