A Google Core Update is a broad recalibration of Google's ranking systems, shipped two to four times a year, that re-weighs how the algorithm reads quality, expertise and answer extractability across the whole index.
Panic-rewriting content during the rollout is the wrong move, and it is the move almost every Australian service business makes. Rollouts take two to three weeks. Any data pulled inside that window is partial. Acting on partial data churns the pages that were about to recover and makes the next diagnosis impossible.
The 2026 cadence accelerated. Four updates by May, against a historical two to three per year. February shipped the first ever Core Update for Google Discover. The March 2026 Core Update and the March 2026 Spam Update landed back to back. The May 2026 Core Update rolled out alongside the I/O AI Mode overhaul, and the Search Engine Journal coverage confirms it weighted E-E-A-T and AI extractability more heavily than any prior core update. The Quality Rater Guidelines were updated in the same window.
Think about it in three windows.
Before, when no rollout is announced on the Search Status Dashboard: this is when the audit happens. E-E-A-T gaps, author bylines, schema, answer extractability, internal linking. Quiet windows are when work compounds.
During, from the announcement to the rollout-complete notice: don't touch anything. Watch the dashboard, log positions, hold the line. Google Search Central is explicit that there is no fix to deploy mid-rollout because the algorithm is still moving.
After, two full weeks past the rollout-complete announcement: now re-audit against settled data. Compare to the pre-rollout baseline. Decide what to change.
A Melbourne service business dropped 30% in week one of the May 2026 rollout, panicked, rewrote nine pages by week three. The rollout completed and they sat at plus 12%. The clean cohorts in the same audit, businesses that held the line, finished at plus 18%. The rewrite cost them six points of recovery and a clean read on which pages actually had a problem.
Topical authority and E-E-A-T are what core updates reward when they settle. SEO & AI Visibility holds the window discipline so the recovery shows up.