Field data.
WHY IT MATTERS
Laboratory measurement is controlled and repeatable. It is not what your visitors experience.
WHAT FIELD DATA REVEALS
The range of devices and connections in use Which pages are slow for real people How performance varies by location
WHAT TO COLLECT
The core timing measurements, from real sessions.
WHAT TO SEGMENT BY
Device type Connection quality Location Page
WHY SEGMENT
Averages conceal that a substantial proportion of visitors have a poor experience.
WHAT TO LOOK AT
The worse end of the distribution, not the average.
WHAT THAT USUALLY SHOWS
Considerably worse figures than laboratory testing suggested.
WHAT TO ALSO COLLECT
Errors occurring in browsers, which you otherwise never learn about.
WHAT TO BE CAREFUL WITH
Collecting more personal data than needed The monitoring itself adding weight
WHAT TO ACT ON
The pages with the most traffic and the worst figures.
WHAT TO MEASURE AFTERWARDS
Whether the change actually helped real visitors.
