Think of document complete time as the time it takes a page to load before you can start clicking or entering data.
Since Google was not clear on what page load time means, we examined both the effects of both document complete and fully rendered on search rankings.
However our biggest surprise came from the lack of correlation of two key metrics!
We then extracted the top 50 ranked search result URLs for each query, assembling a list of 100,000 total pages to evaluate.
Next, we launched 30 Amazon "small" EC2 instances running in the Northern Virginia cloud, each loaded with an identical private instance of the open source tool Web Page Test.
In other words, this metric encompasses the network latency of sending your request to the web server, the amount of time the web server spent processing and generating a response, and amount of time it took to send the first byte of that response back from the server to your browser.
The graph of median TTFB for each search rank position is shown below: The TTFB result was surprising in a clear correlation was identified between decreasing search rank and increasing time to first byte.
Now, the speed at which someone could view the content from a search result would be a factor.
Unfortunately, the exact definition of "site speed" remained open to speculation.
Matt Peters, data scientist at Moz, asked Zoompf to help find the answers.
While Google has been intentionally unclear in which particular aspect of page speed impacts search ranking, they have been quite clear in stating that content relevancy remains king.
While we'll summarize the results below, if you want to check out the data for yourself you can download the entire result set here.