Google analytics, bounce rates and search rankings

This probably says more about the nature of my working day than I should admit to publicly, but we are currently thinking more about what Web site analysis tools we should make use of here for the Eduserv Web sites.  This caused me to go and have a look at the Google Analytics pages for the Newbridge Primary School Web site (which I help to maintain in my spare time), which caused me to notice the school's bounce rate, which led me to this (slightly old)  research on the Google bounce factor, which ultimately got me thinking!

OK, so what's a bounce rate?  A site's bounce rate (as far as I can tell) is the proportion of people that visit your site (via a search engine, or from a bookmark, or via another Web site, or whatever) and immediately go back to where they came from.  The implication is that they didn't find what they were looking for.  The bounce rate on the school site is around 50%, which seems quite high to me.  (One explanation for this, though I don't know how plausible it is, is that people are looking for the school calendar, which is on the home page, and therefore as soon as they have seen it they go back to the search engine to go on somewhere else.)

What the research above says is that the more times people click on your link in Google search results, the better your ranking gets.  This is good.  But on the downside, the more times people immediately bounce back to Google, the worse your ranking gets.

I don't think this will come as much of a shock to most people.

What Google Analytics does though is to give Google information about how long people are staying on your site.  The implication is that Google also uses this information, in addition to simple bounce rates, to raise or lower a site's ranking.  If people stay on your site a long time, then your ranking will go up - if they don't, it will go down.

The bottom line, or at least a potential bottom line, is that if your bounce rate is high or your average length of visit is low (for whatever reason - and it seems to me that there might be very good reasons for both of these being true) then running Google Analytics may not be in your best interests in terms of search results rankings?

If anyone reading this knows more, please feel free to comment...