_:n0bd2443db48e43fcba7dcd00b9c79b2dxb3
<http://schema.org/text>
"<p dir=\"auto\">Hi Niels - yep, I saw a bit of this too. I believe there's two causes:</p>\n<ol>\n<li>\n<p dir=\"auto\">We crawled a larger swath of the web in this index, so we captured more sites and more links, and that may mean the scaling of PA/DA (which are logarithmic) stretches to accommodate the larger number of links found, especially to sites at the top of the scale. For example, if Facebook has a DA of 100 with 5 Billion links, then we find 5 billion more links to it, Facebook still has a DA of 100, but it's a much higher threshold. Thus, sites with fewer links (and less quality links) will fall in DA as the scale is now stretched.</p>\n</li>\n<li>\n<p dir=\"auto\">We crawled some weird stuff in this index, by mistake (or rather, because spammers built some nasty, deep crawl holes that Google probably didn't fall for but we did). A ton of odd domains on strange ccTLDs were seen, and crawled, because they gamed PageRank with lots of sketchy links. We've now excluded these for indices going forward, and hopefully will see the impact abate.</p>\n</li>\n</ol>\n<p dir=\"auto\">All that said, over time, as our index grows, you can expect that raw DA/PA numbers could get harder to achieve, meaning a lot of sites will drop in PA/DA (and some will grow too, as we discover more links to them in the broader web). My best advice is always to not use PA/DA as absolutes, but rather relative scores. That's how they're designed and how they work best.</p>\n<p dir=\"auto\">It's like back when Google had PageRank, and <a href=\"http://Moz.com\" rel=\"nofollow ugc\">Moz.com</a> grew from PR4 to PR7, then as Google got bigger and bigger, and the web got bigger, <a href=\"http://Moz.com\" rel=\"nofollow ugc\">Moz.com</a> fell to PR5, even though we had way more links and ranked for way more stuff. The raw PR scale had just become stretched, so our PageRank fell, even though we'd been improving.</p>\n"
<https://moz.com/community/q/topic/62103/is-everybody-seeing-da-pa-drops-after-last-moz-api-update/25>