What Triggers AI Overviews? 86 Factors and 146 Million SERPs Analyzed

What triggers an AI Overview? What types of queries are most likely to generate an AIO, and which are relatively safe? Can we predict where AIOs will appear, and even target SERPs without them?

To answer these questions, we analyzed our database of 146 million SERPs and explored how often AI Overviews appeared for 86 different keyword traits, from YMYL to CPC to query length.

Across our data set, AI Overviews appear for 21% of keywords. But looking at specific keyword categories, some categories have as high as a 60% chance of triggering an AI Overview, and others as low as 1%.

Keywords Explorer and use the SERP features filter to see all keywords that trigger an AI Overview, and filter by dozens of variables like intent, volume, and growth rate:

You can also analyze any brand, website, or product’s visibility in AI Overviews using Brand Radar.

Just enter your brand to analyze your mentions, citations, estimated impressions, and even share of voice across millions of AI Overviews:

Google themselves—deserving of extra care and attention, it seems surprising to see AI-generated answers so prevalent.

In fact, AI Overviews are more common for YMYL queries than normal queries. 34.3% of all YMYL queries trigger an AI Overview, far higher than our 20.5% baseline. Non-YMYL queries are less likely to trigger AIOs, at just 17.2%:

Label AIO SERPs All SERPs Percent
Not YMYL 20291372 117843464 17.2%
YMYL 9700626 28278927 34.3%

All YMYL categories—Medical, Financial, Safety, Legal, and Other—show an increased occurrence of AI Overviews.

This is especially true for Medical YMYL queries, with 44.1% of medical queries triggering an AI Overview—more than double the frequency at which AI overviews appear across all keywords.

Category AIO SERPs All SERPs Percent
Not YMYL 20291372 117843464 17.2%
Medical 5924866 13430263 44.1%
Financial 2027902 8859397 22.9%
Safety 1215129 3922977 31%
Legal 354573 1499855 23.6%
Other 178156 566435 31.5%

This has not gone unnoticed by SEOs in the healthcare industry:

Mark Williams-Cook found a series of query classifiers used by Google as part of their search systems. (Learn more here.)

All but one of these categories (other) are much more likely than average to trigger an AI Overview. At the extreme, 59.8% of all reason queries trigger an AI Overview, the greatest percentage of any category in this research.

Category AIO SERPs All SERPs Percent
other 6999483 91932424 7.6%
short_fact 6462155 15700313 41.2%
definition 5208895 11001131 47.3%
reason 4603040 7696962 59.8%
instruction 4394332 12521507 35.1%
comparison 1292772 4942567 26.2%
bool 772554 1346630 57.4%
consequence 219770 470434 46.7%

Search Quality Evaluator Guidelines:

  • Know query, some of which are Know Simple queries
  • Do query, when the user is trying to accomplish a goal or engage in an activity
  • Website query, when the user is looking for a specific website or webpage
  • Visit-in-person query, some of which are looking for a specific business or organization, some of which are looking for a category of businesses

99.9% of the keywords that trigger AIOs fall into the “Know” category, suggesting strong overlap between Know keywords and our definition of Informational keywords (which also account for 99.9% of AIO triggering keywords). Google seems unlikely to trigger AIOs for other intent types.

Category Count Percentage
know 29,959,549 99.9%
do 2,755,518 9.2%
visit_in_person 628,188 2.1%
website 26,411 0.1%

Do, Visit-in-person, and Website all trigger AIOs less frequently than the base rate, with Website queries returning them less than 1% of the time.

The Visit in person AIO rate is virtually on par with our Local queries category (7.1% and 7.9% AIO rate respectively); and the Website AIO rate is identical to our Navigational classification from earlier (both returning an AIO rate of 0.9%).

Category AIO SERPs All SERPs Percent
know 29959549 140287274 21.4%
do 2755518 21168986 13%
visit_in_person 628188 8813799 7.1%
website 26411 2909983 0.9%

Final thoughts

It seems crystal clear that AI Overviews are designed to trigger for informational queries, particularly questions and long queries. They are unlikely to trigger for news queries, local searches, and NSFW queries.

But more surprising: AI Overviews trigger very frequently for YMYL queries, and especially medical YMYL queries. Despite obvious risks of hallucination, Google seems perfectly happy answering crucial medical queries with an AI-generated snippet.

Further reading

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