A lot of articles and How-To guides on Search Engine Optimisation (SEO) include something called Bounce Rate.  It is said that it affects how high up in Google's search results you appear (i.e. your search ranking).

This is not completely correct.  Even though it is a statistic worth paying attention to, the Bounce Rate reported in Google Analytics is not used to calculate where you appear in Google.

What is bounce rate and should I care?

Bounce rate is the percentage of visits that come to your website then leave again without going to another page on your site.

This is reported in Google Analytics:

High rates are considered BAD.

Why? Because it suggest that the visitor didn't get what they wanted. They weren't interested so left again without buying anything, signing up for anything or filling out your contact form.

If an unsuspecting individual searches for something, clicks on a result and are taken to a site chock full of ads that is so terrible they leave again within seconds – this is counted as a bounce.

But let's say you have written the most AMAZING blog post about getting rid of the Hemlock weed from the garden. One that is backed up by research and is the definitive guide. One that, once read, means I'd never need to read another article about it ever.
A visitor comes to the site, reads the article and is completely satisfied with all the information. They leave again without looking around the rest of your site. But - they write on Facebook about this amazing article and shares a link it with all their friends. This is a GOOD result, even though Google Analytics would still calculate this as a bounce.

Why do people say it affects SEO?

Perhaps because bounce rate implies a bad website experience, on the surface. There is an assumption that a good site will draw people in and they will look around. That if the Big G knows you have a high bounce rate, it will think your site is bad and will banish it to the search result doldrums.

But correlation does not imply causation.

Why it DOESNT affect SEO

SEO factors are often hotly debated, so let's put a technical SEO discussion to one side, and take a simple, common sense perspective:

1. Not all sites have Google Analytics. A lot of small businesses do, but many corporate sites don't. They use other commercial measurement tools and Google does not have access to this data, so they don't know what the site bounce rate is. Do you think Google is going to penalise leading companies who are experts in their field because of this? Probably not.
2. Google says in this video they don't use Analytics data. Lets assume they are telling the truth.
3. Or, let's assume Google isn't telling the truth and does use this data. But tracking code can be manipulated or implemented incorrectly. So the data is dodgy – which is why it is more likely that Google is actually telling the truth, because they don't like it when people game their system.
4. Google et al are smarter than you or that twenty-something-year-old web developer thinks. Google understands that bounce rate, as measured by Analytics, is a poor indicator of quality in absolute terms

Why you should still care about Bounce Rates

Bounce rates are an indicator of quality depending on the nature and purpose of your site. If you want people to sign up for your blog or take some other action, then high bounce rates are probably a bad thing. It tells you either the quality of your traffic is poor (ie you are attracting the wrong visitors) or your site is not delivering on it's promise.

High bounce rates are often (though not always) linked with low conversion rates.

Isn't quality important to Google?

The search engines DO care about quality.  If a person clicks on a search result, thinks "Gah! This is Horrible" and immediately returns to the search engine results – this implies a poor experience with that website. And quite rightly that site shouldn't rank as high as better quality competitors (depending on other factors).

The cynic/realist in me would also point out that quality search results means people will continue to use that particular search engine.  Which in turn means said search engine will sell more ads, so quality is in the search engines best interests. 

Introducing: Dwell Time.

The search engines can measure the time between someone clicking on a search result and the amount of time before they come back again - assuming they do return to the search engine results within that session.

If a searcher clicks on a search result and bounces back within seconds, this is a short dwell time. It is indicative of a poor search result. If they click on a search result and don't bounce back for ten minutes or more, then this is a long dwell time.  It is still a bounce, but not perceived negatively.

Some SEO's use this calculation and call it a bounce rate somewhat interchangeably with the bounce rates reported by Google Analytics.  This may have contributed to some of the confusion. And there MAY be a corrrelation between your bounce rate as reported by Analytics and your dwell time for certain search terms.

What about Click Through Rates.

Another behaviour the Search Engines can measure is Click Through Rate (CTR).  This is how many people actually click on your search listings.

A high percentage indicates value. Low suggests the result is not seen as valueable. Top results will get higher click through rates than the second result anyway.  And this has a higher CTR than the third result and so on.  But what if the third result had a higher CTR than the one in the top spot?  What would this tell Google about the result?  I'd expect Google to notice that the third result is seen as a better one than the top one.

This CTR data is available via Webmaster Tools. You can influence your ranking CTR by optimising Title and Description tags.  Search Engine Watch wrote a useful article on this.

Last Word

Finally, remember that organic search rankings are the result of a combination of factors - a single ranking factor like CTR or Dwell Time (or bounce rate) will not determine your search ranking on it's own.

And as always, focus on quality content that solves a problem for your audience. Make it special. Make it unique. Make it often.

If your site is good it will rank well and incidentally have a low bounce rate.  Stop worrying about bounce rate for SEO and worry about bounce rate for your user experience.

Final Last Word

Several blog posts on this site rank on Google's first page for related search phrases. This is despite this site not being well optimised in it's present form - and the posts having bounce rates over 80% or 90%.

And that is good enough proof for me.