A core update is a broad change Google makes to its ranking systems several times a year, affecting all kinds of sites and queries at once. Google's position is that a page which drops after one is not necessarily broken; other pages are now judged to serve the query better. The right response is to wait, compare, and then assess the site honestly rather than to rush changes.
What Google says they are
Significant, broad changes to search algorithms and systems, made several times a year and announced on Google's status dashboard. They are distinct from the smaller improvements that ship constantly and from targeted updates such as spam or reviews updates. Since March 2024 the helpful content system has been part of core updates rather than a separate one.
Google frames a drop as a reassessment rather than a penalty. Nothing has been done to your page; the yardstick moved.
How to tell an update from your own mistake
Timing and breadth. An update moves many sites in the same week, and it moves your rankings across many keywords at once rather than on one page. A mistake, a broken redirect, a noindex left on after a redesign, an expired certificate, usually starts on the day something was deployed and hits the pages that were touched.
This is what annotations are for. If your ranking chart shows the drop starting the day of an announced update and no note of your own that week, it is the update. If it starts the day you changed the theme, it is the theme.
What Google says to do
Wait at least a week after the update finishes rolling out, then compare before and after in Search Console. Small movements, a couple of positions either way, need no action. For large drops, work through Google's self-assessment questions about whether the content is helpful, reliable and written for people, and fix what falls short.
Recovery is not fast and not guaranteed. Google says improvements can take several months to be recognised, and that some sites will not see the effect until the next core update. Ripping the site up in the meantime tends to make things worse.
Where this shows up in the tracker
Announced updates are recorded against every ranking chart, so a drop lands with its context attached. Search Console data is kept for the full sixteen months Google provides, which is enough to compare this update with the last one rather than only with last week.
Sources
Where this shows up in the tracker
Every term in this glossary is something the product actually measures or acts on. Plans start at £29 a month, with rank tracking, AI visibility, the daily AI readiness scan, security and domain health, Search Console, backlinks and audits on every one of them.
Related terms
Helpful content update
The helpful content update was a Google ranking change first released in August 2022 that assessed whether a site's content was written primarily for people or primarily to rank, and applied a site-wide demotion where it judged the latter. The September 2023 version caused severe losses for many small publishers. In March 2024 Google folded the system into its core ranking systems, so it no longer exists as a separate signal.
Thin content
Thin content is a page that offers a visitor little or nothing they could not get elsewhere: empty category pages, copied product descriptions, auto-generated text, a paragraph wrapped around an advert. Google has no minimum word count and says so. A short page that answers a question is not thin. A long page that says nothing is.
E-E-A-T
E-E-A-T stands for experience, expertise, authoritativeness and trustworthiness. It comes from the guidelines Google gives the human raters who evaluate search quality, not from the ranking algorithm. Google says E-E-A-T itself is not a ranking factor and that rater data is not used directly in ranking. It describes what Google's systems are trying to reward, which makes it a useful checklist and a poor thing to optimise for directly.
CTR
Click-through rate is the share of people who saw your result and clicked it: clicks divided by impressions, shown as a percentage in Search Console. It falls steeply with position, so it only means anything when compared against the position it was earned at. Whether Google uses clicks to rank is a question with two honest halves, covered below.