This is an oldie but a goodie. SEO specialists know this already. You should too, if your internet business depends on traffic from Google at all.
Back in August 2006, AOL (TWX) released the search records of 500k users collected over a three month period. The data was removed as quickly as it was published, due to privacy concerns. It is still available on various mirrors on the internet, however (nothing is ever completely erased from the internet).
Then Richard Hearne of Red Cardinal took the data and figured out the average click-through rate of each position on Google’s search results page:
SEO specialists and internet marketers can then use this data, cross-reference it with the Google’s Keyword Tool, and figure out potentially how much traffic they can receive per keyword if they’re able to achieve a high search engine rank.
How reliable is this data? Pretty reliable, since the selection size is so large. There may be some bias (they were all AOL users), but I’m guessing it’s fairly accurate. Ed Dale believes it’s pretty spot on.
A couple of months later, several researchers from Cornell University did an eye-tracking analysis of Google’s search results page. They came up with slightly higher click-through percentages, as Oleg Ishenko of SEO Researcher shows with the following heat map:
The Cornell study is less reliable, however. Their sample set was only 26 undergraduate students who performed 397 Google queries in a usability lab.
In either case, these results show a strong click-through rate for the first result (no duh). The rates taper down until the last result, which enjoys a slight uptick. It should also be noted that this data only shows rates for organic search results and not PPC/sponsored listings.
Cool stuff though. I love free data.