Google announced a revision to Google Analytics with regard to Site Speed on Friday, November 18, 2011. The speed at which the pages of your website load has been a talking point for a while, with Google working on tools to gauge the performance of your pages in Google Analytics and Google Webmaster Tools. Ideally, a page with a high average page load time could be analyzed and possible factors increasing load time addressed. As a matter of foreshadowing, Matt Cutts wrote a blog post on April 9, 2010 entitled, “Google incorporating site speed in search rankings,” which stated that Google had incorporated Site Speed amongst the signals used to determine search rankings.
Previous to this Google Analytics Site Speed announcement, website owners who wanted to track their Site Speed in Google Analytics had to add an additional line of tracking code into their GATC to gather the data for the Site Speed report:
This is no longer necessary.
The _trackPageview method (_gaq.push(['_trackPageview']);) controls the data collection, which feeds the Site Speed report.
If you have a firm foundation in Statistics and wish to be able to control the sample size collected by Google Analytics — currently, Google Analytics collects 1% of visitors or 10K hits per day — you can use the _setSiteSpeedSampleRate() method (_gaq.push(['_setSiteSpeedSampleRate', 5]);) which should be added before the _trackPageview method in the GATC.