What is Google Analytics "Avg. Page Load Time"

Question

What exactly is the metric "Avg. Page Load Time" in Google Analytics?

I would expect it to mean the same thing as "Avg. Document Content Loaded Time (sec)":

"Average time (in seconds) that the browser takes to parse the document and execute deferred and parser-inserted scripts (DOMContentLoaded), including the network time from the user's location to your server."

"Avg. Page Load Time" is described as:

Google Analytics Help says that it is "Avg. Page Load Time is the average amount of time (in seconds) it takes for pages from the sample set to load, from initiation of the pageview (e.g. click on a page link) to load completion in the browser. If you see zero (0) as a value or a small increase in November 2011, read the About Site Speed article."

... but what exactly is "load completion"?

The reason I'm trying to sort this out is a > 4x difference in "Document Content Loaded Time" and "Page Load Time" ... but when I render it in my browser I'm not seeing anything that takes nearly that long.

Answer 1

Essentially the speed analytics are measuring different points in the timeline, Average page load time is the whole load time including all parts of the timeline and Document content loaded time is just a small part of the time line.

The speed you see reflected in the stats and the actual experience you get can be due to a number of factors, They can include redirects and serverside processing and scripts loading in the background all things you dont really see or experience.