Algorithm
Core update
A broad Google algorithm update affecting search rankings sitewide rather than a single feature. Recent core updates (e.g. May 2026) have increasingly favoured intent-aligned content over keyword-optimised content.
What it is
A broad Google algorithm update that recalibrates how relevance and quality are assessed across the whole index rather than tuning one feature or content type. Recent core updates have shifted weight towards intent-aligned content over content that is merely keyword-optimised.
Why it matters
Core updates can reorder rankings sitewide overnight, so they directly determine which pages remain discoverable and which sources AI Overviews draw from. A single update can erase or multiply organic visibility without any change to the page itself.
How it works
Google reassesses the relative quality and intent fit of pages against refreshed signals, so the response is to improve genuine helpfulness and intent coverage rather than chase the update with quick tweaks. Recovery typically arrives only at a later update once the underlying quality has lifted.
When it applies
They roll out roughly three to four times a year and take two to three weeks to fully deploy.
Examples
- A thin comparison page outranked by a slimmer guide that answers the searcher's actual question more directly.
- A site built for keyword density losing ground to one organised around user tasks and intents.
- Rankings shifting during the rollout window then settling into a new order once deployment completes.
How it is measured
- Sitewide change in average position before and after the rollout window
- Share of impressions and clicks by intent cluster
- Number of queries gained versus lost across the catalogue
- Proportion of ranking pages cited in AI Overviews post-update
Related terms in Algorithm
- EEATGoogle's quality framework: Experience, Expertise, Authoritativeness, Trustworthiness. EEAT signals are increasingly weighted in both classical ranking and AI Overview source selection.
- Helpful Content UpdateGoogle's quality-focused update class targeting low-value, AI-generated, or thin content. Successive HCUs have favoured first-hand experience and named expertise over comprehensive but shallow coverage.
- SERP volatilityThe rate of change in search result rankings over a time window. High volatility usually signals a core update or major spam action in progress.
- Topical authorityThe perceived depth and breadth of a domain's coverage of a topic. Post-HCU, depth + first-hand expertise are weighted more heavily than breadth.