Basically the bounce rate is the percentage of people that come to your site and leave immediately or after only a few seconds. This is a good measure of the quality of your visitors and lets you know what you need to improve on your website in order to keep people there.
If you use Google Analytics then you will see they use the following definition of bounce rate:
"Bounce rate is the percentage of single-page visits (i.e. visits in which the person left your site from the entrance page). Bounce rate is a measure of visit quality and a high bounce rate generally indicates that site entrance (landing) pages aren't relevant to your visitors."
This clearly shows that Google thinks bounce rate is an indication of relevance. The aim of Google is to return the most relevant results in the search engines and so it could be said that if you have a high bounce rate you are not relevant and so should be lowered in the rankings.
Is Bounce Rate a Google Ranking Factor?
We already know that Google collects the bounce rate of a website by using its Analytics program and through the Google toolbar. Combined with the fact it sees bounce rate as an indication of relevance it would be a good assumption that bounce rate is a ranking factor. However how can we really know for certain.
It is unlikely that bounce rate will be the main ranking factor but if you are a website that has a good SEO campaign and begins to appear high up it may affect you. Let's suppose you appear on page 1 of Google for your chosen search term but have a bounce rate of over 50% it may cause Google to drop you off page 1 in an attempt to return more relevant results.
How to Lower you Bounce Rate
If you have a high bounce rate of say 70% it might indicate that the contents of the page are not good and that it is not easy to navigate your website. In order to improve your bounce rate you want to improve your contents and make your site easy to navigate.
We would recommend having a look at the websites that come at the top of the search engines for your chosen keywords. What do they do, how do they structure their content and what is their navigation like. Obviously you don't want to copy them but you want to see what they are doing so you know what the right way is. Compare them with your site, if there are noticeable differences then you might want to change your site to make it more interesting and user friendly.
Doing this could mean you make you site more interesting and so reduce you bounce rate which should prevent Google from dropping you down the rankings.
It is important to point out that your bounce rate will probably nor move you hundreds of places in the rankings but it could mean the difference between you being in the best possible place to being in an ok place.
