Leveraging the Metrics that Most Affect User Experience: #io17

A few days removed from Google #io17, and a few things were very apparent: the performance conversation is vociferous. The annual event which doubles as a company SOTU and road map. The performance conversation was clear and spread through just over 150 talks - about the divisive AMP, emerging markets, the mobile web and user experience and metrics.
One of the early talks was just about that, #ux. Leveraging the Metrics that Most Affect User Experience by Google engineers Philip Walton & Shubhie Panicker. Despite all the tools available, how can we keep on eye the real user metrics?

The load isn't one single moment, it's an entire experience, and can't be represented by a single metric. - Philip Walton. Developer Program Engineer.

The entirety of the talk could be summarized with the above, but they essentially deep dive into greater detail.

Load is a very small fraction of the entire user session. Users associate performance with their entire experience. - Shubhie Panicker. Staff Software Engineer.

How do you maintain a pristine user experience? The tools we have on hand are great: from DevTools to Lighthouse and even WebpageTest are all great at catching early issues before you go live (and even when you do to an extent) but all are synthetic, or what Shubhie Panicker refers to as in lab, and urges that real world testing is a must. Reasons are clear: recalcitrant networks, diverse devices, capricious caching conditions, all adversely affecting the user experience, and metrics not easily captured. What needs measurements:

  • First paint
  • First contentful paint
  • First meaningful paint
  • Time to interactive.

And much time is spent discussing the latter of the four as Shubhie puts it:

Interactivity is a crucial part of load, but is often neglected. - Shubhie Panicker. Staff Software Engineer.

This then leads to the conclusion that javascript management is key in the entire battle. It's locking of the main thread is the reason devices are victims of long tasks, and by default victimizing the users as well.

Both Philip Walton & Shubhie Panicker go into greater detail on how Google Chrome is tackling performance and the metrics. A great talk full of good information and detail. Enjoy.