Google Research has released a new study looking at how often ad impressions are accompanied by associated organic results and how the incrementality of ad clicks vary with the rank of those results.

Google posts the following highlights on its Inside AdWords blog:

• 81% of ad impressions and 66% of ad clicks occur in the absence of an associated organic result on the first page of search results. All ad clicks in these situations are incremental.
• On average, for advertisers who appear in the top rank organic slot, 50% of ad clicks are incremental. This means that half of all ad clicks are not replaced by organic clicks when search ads are paused.
• For advertisers whose organic search results are in the 2nd to 4th position, 81% of ad clicks are incremental. For advertisers appearing in organic position of 5 or lower, 96% of ad clicks are incremental.

On the Google Research blog, they posted the following infographic looking at the findings:

Google is careful to note in the study’s concluding remarks that results will vary for individual advertisers, and that advertisers with similar IAC (Incremental Ad Clicks) estimates may have very different organic rank for the terms in their ad campaign. Advertisers with similar organic rank may have very different IAC estimates.

Here’s the study in its entirety (pdf).