November 23, 2011
How frequently does mozrank refresh?
Here's useful info from the CEO of mozrank:
Hey gang – I'm the CEO and founder at SEOmoz (we build the Linkscape web index from which mozRank is derived). I figured I could provide some more information about the differences here.
MozRank – obviously, it's not directly from Google. We calculate it in much the same way the original Google PageRank formula is described here (http://infolab.stanford.edu/~backrub/google.html) with a few changes we're fairly sure Google's made since then. It's calculated once monthly, at the same time as our new indices are released (you can read about those in posts like http://www.seomoz.org/blog/november-…nkscape-update). The metric provides accuracy to two significant decimal places, but it's across our web index rather than Google's. We index ~40-60 billion URLs per update, which we estimate to be approx 1/2 of what Google keeps in their main index. Correlation between mozRank and PageRank is typically quite high just after a PR update, and then trails off as PR scores get less fresh (more detail here: http://www.seomoz.org/blog/the-scien…g-correlations).
Google PR – comes via Google's toolbar (or via the checksum hack). It's updated every 3 to 12 months (Google's fairly random about these updates, so it's hard to know if/when one's upcoming). That said, because it's Google, the data is generally more comprehensive (they cover more URLs, particularly deep ones in less important sites or far down on large sites) and they'll include PR penalties (mozRank will not, because we don't have Google's sophistication in spam filtering).
All that said, if you're going to use a metric to value a webpage/website, Page Authority and Domain Authority (also via the Linkscape index) are FAR superior metrics to either PR or mR from a correlation to rankings perspective. Hope this is helpful! [Source]