How is Moz Page Authority Calculated?

[GlennFerrell]

Can anyone refer me to a document that explains the measures that go into the calculation of Moz Page Authority? I'm chiefly interested in what counts and what doesn't  -- follow links, no-follow links, internal and external, what (if any) on-site factors, etc.

[Ria_]

Moz's page on what Page Authority is:

https://moz.com/learn/seo/page-authority

[GlennFerrell]

So it sounds like it's intended as a proxy for Google Pagerank.