Is bounce rate a (Google) search engine factor?

I believe someone (perhaps a competitor) is trying to manipulate the bouncing rate of one of my sites. So I'm tryi开发者_开发知识库ng to figure out if this has any impact on search engine ranking, and take appropriate action.

I have read mixed opinions about this, but couldn't find a definitive Yes or No anywhere.

Edit: If the answer is yes, I hope Google considers repeated bounces (coming from the same user) as an additional variable in their bouncing rate calculation algorithm. Otherwise, anyone could set a bot to bounce every x minutes.

Quoting this article.

Google has the ability to collect the bounce rate with the Google toolbar and Google Analytics. In addition, Google can measure the time between visits to their search engine by the same user and they can use the Google Chrome browser to measure the complete surfing behavior of users. Last month, a webmaster performed a test that showed a significant ranking change as a result of a significant bounce rate change. The test is not very conclusive but chances are that Google really uses the bounce rate as a ranking factor. The bounce rate alone might not be used by Google but combined with other factors, it could have an effect on the rankings. For example, Google could measure how many people start a new search for the same topic after visiting your web page. That would be an indicator that your website is not suitable for the chosen keyword.

Bounce rate is important for SEO, the lower the better. Is that guy just going to your site and close it and then repeat ? If yes than usually Google can identify behavior which is unnatural. Also either he has to sit all day and do this, or your site needs to have a really low visitor count for him to be able to affect you.