User Focused Metrics

As developers for the Web, we need metrics that accurately describe the customer experience.

Up until not so long ago the Web industry looked to browser timing marks like onLoad or onContentLoaded (DOM ready), but unfortunately, these metrics only tell us how long it took to deliver assets to the browser.

We need metrics that describe what users are seeing and experiencing, without having to watch recordings of every single user session.

Calibre records a number of metrics that aim to break down the key points between a user entering a URL and the page being ready for interaction.

To understand the difference between those metrics, have a look at the following image portraying the render cycle:

Metric Definitions

  • First Paint: the browser changed from a white screen to the first visual change
  • First Contentful Paint: first text is rendered
  • First Meaningful Paint: text, images, buttons and major items are viewable
  • Visually Complete: all content in the browser viewport is visible

Each of these timings are fantastic candidates for optimisation because they directly translate to what the user sees.