The same query in ten countries shares about half its results
Run an identical query from nine other countries and roughly half the domains change.
20 Aug 2026
The gl parameter looks like a detail. It is two letters, it defaults to us, and most integrations set it once and never revisit it.
Measured across our corpus, changing it changes about half the answer. Result sets from nine countries share on average 50.7% of their domains with the same queries run from the United States. The furthest apart is France, at 50.2%.
Why the number is a Jaccard coefficient
Counting shared domains in the top ten sounds simpler and is worse: Google does not always return ten results, so a raw count moves when the page length does. Dividing the intersection by the union removes that, and the figure then describes the result sets rather than their length.
What it means in practice
A rank tracker configured for one country is not measuring a slightly different page from the one your buyers in another country see. It is measuring a substantially different one. If you sell internationally and track domestically, the gap above is the size of your blind spot.
Country by country: the report, or the market index.
Run the same measurements yourself
Free tier, no card. Every figure above came from one endpoint on a weekly schedule.