Definition of Page Authority
This ranking depends on the Mozscape indicator and also the number of internal links "Backlinks", MozRank, MozTrust, and many other factors. It uses a predictive method to determine the compatibility of this page with search engine algorithms, and compare it with other sites in the same domain as your page.
MOZ evaluates the Page Authority from 1 to 100 points, as this scale is logarithmic. It is therefore easy to increase your rating from 20 to 30 and may rise from 70 to 80. The MOZ constantly updates this algorithm to calculate the Page Authority, so you may see your site's rating changing from time to time.
Page Authority vs. Domain Authority
While Page Authority is a measure of the power of pagerank as each page gets a different evaluation from the other page, unlike the domain authority it measures the strength of the domain in general.
How to calculate page authority?
How to improve page authority?
It is difficult to directly affect the page authority. It depends on a set of metrics as mentioned previously (MozRank, MozTrust, link profile, and many other factors) and each factor has a different effect.
This metric is determined by determining how closely a page is in Google. Google has a lot of factors in ranking search results, and MOZ also includes some of these factors in its ranking.
The best way to influence this metric is to optimize the pages of your site in general with Google. In particular, you should focus on your evaluation of MozRank and MozTrust and you can increase the rating by getting a high quality backlinks from sites in the same niche of your site.