Accurate metrics for response time and uptime are gathered through the use of Pingdom and Catchpoint.
Uptime is measured in 30-second intervals through Pingdom. Three geographically dispersed nodes attempt to ping each website, and if all three nodes fail to receive a response, downtime is recorded.
Page load time is measured once every 4 hours through Catchpoint. Chrome and Internet Explorer are used as web browsers. A full page load (including text and images) is completed and the time (in milliseconds) is recorded upon completion of the full load.