Does Google measure bounce rate?
Here is a question that no one outside Google knows the answer to. Does Google take bounce rate into account when ranking your pages? The answer is probably not because it could only get the real bounce rate from Google Analytics and as every site does not have Google Analytics installed it, it would seem unfair to penalize those that do.
There is speculation that Google could track bounce by tracking sessions and noting when you click on a link in its search results and then if you click on another link, thus realizing that the first click did not give your the answer you were looking for because you are continuing to search. But again this would be unfair as you may simply need more then one answer to your question.
What could be a ranking factor though is how many times your link is clicked on when it is presented to the user as a choice, this of course would be weighted for positioning on the page, but many speculate that your click-through rate does affect your position.