Algorithm Update
An algorithm update is a change Google makes to how it ranks pages. Broad core updates run a few times a year and reshuffle results widely. Smaller updates target specific problems such as spam, reviews or helpful content, and often go unannounced.
Why it matters for your rankings
Updates are how the ground moves under your rankings without you touching anything. A site can lose a third of its traffic in a week because the definition of a good result changed, not because the site got worse in absolute terms.
Understanding which update hit you determines the fix. A core update usually signals a relevance and quality reassessment, which content work addresses over months. A spam update signals something specific and often fixable, like purchased links. Reacting to a core update by rewriting titles wastes a quarter. The other risk is misattribution: teams blame updates for drops actually caused by a botched migration, a noindex tag or seasonality, and then chase the wrong problem entirely.
How to check it on your site
Pin the exact date of the drop
In Google Search Console open Performance, set a 16-month window and compare clicks week over week. Note the precise day the decline started.
Match it to a confirmed update
Check the Google Search Status Dashboard and a tracker such as Semrush Sensor for a named update on that date. If nothing matches, the cause is probably your own site.
Segment the loss
Filter Search Console by page and by query. A drop concentrated in one template points at a technical or content problem. A drop spread evenly across the site points at a sitewide quality reassessment.
Rule out self-inflicted causes
Confirm no deploy, redirect change, robots.txt edit or CMS migration landed the same week. This is the single most common cause of drops blamed on updates.