Metric loss

Google creates new core Web Vitals metric

In a recent HTTPArchive Almanac article on CMS usage around the world, the author mentioned that all platforms perform well on First Input Delay (FID), a Core Web Vitals metric, and that Google is working on a new metric, which could replace First. Entry delay (FID).

Each year, HTTPArchive publishes several articles on the State of the Web. Chapter 16 deals with content management systems (CMS). The article was written by a backend group manager and web performance engineer at Wix and reviewed and analyzed by various Googlers and others.

The article raised an interesting point about the loss of meaning of the First Input Delay metric and mentioned how Google was developing a new metric.

First entry delay

Core Web Vitals is a group of user experience metrics designed to provide a snapshot of web page performance for users and First Input Delay (FID) is one such metric.

FID measures how quickly a browser can respond to a user’s interaction with a website, such as the time it takes for a response to occur when a user clicks a button on a website. website.


Continue reading below

The thing about FID is that all of the major content management systems like WordPress, Wix, Drupal, and others all have lightning-fast FID scores.

Everyone wins an FID trophy

The article first mentions that most CMSs get an exceptional score for FID. And the platforms with the lowest scores still have relatively high scores that are only 5 percentage points behind.

The author wrote:

“FID is very good for most desktop CMS, with all platforms getting a perfect score of 100%. Most CMSs also offer a good mobile FID of over 90%, with the exception of Bitrix and Joomla with only 83% and 85% of origins having a good FID.

What happened to FID is that it’s basically a measure where everyone gets a trophy. If almost all sites are doing great, if everyone is getting a trophy, it means that there really is no reason for the metric to exist as the goal of correcting this part of the user experience has been achieved.


Continue reading below

The article then mentions how Google (the Chrome team) is currently creating a new metric to measure responsiveness and response latency.

The article continued:

“The fact that almost all platforms manage to deliver good FID has recently raised questions about the thoroughness of this metric.

The Chrome team recently published an article, which detailed the thoughts to have a better responsiveness metric in the future.

Entry response time versus full event duration

The article is linked to a recent Google article posted on titled Feedback Wanted: An experimental responsiveness metric.

What’s important about this article is that it reveals that Google is working on a new entry delay metric. Knowing this metric can give you a head start in preparing for what’s to come in the future.

The main point to understand about this new metric is that it doesn’t just measure unique interactions. It measures groups of individual interactions that are part of a user action.

While the article cited in HTTPArchive cited an article from November 2021 asking for comments from editors, this new metric has been in development for some time now.

A article from June 2021 described these goals for the new measure:

“Consider the responsiveness of all user input (not just the first one)

Capture the total duration of each event (not just the delay).

Group the events that occur as part of the same logical user interaction and set the latency of that interaction as the maximum duration of all of its events.

Create an overall score for all interactions that occur on a page, throughout its lifecycle.

The article says the goal is to design a better metric that encompasses a more meaningful measure of user experience.

“We want to design a metric that better captures the end-to-end latency of individual events and provides a more holistic picture of a page’s overall responsiveness throughout its lifespan.

… With this new metric, we plan to extend it to capture the entire duration of the event, from the initial user input until the next frame is painted after running all the handlers. events.

We also plan to measure interactions rather than individual events. Interactions are groups of events that are dispatched as part of the same logical user gesture (eg pointer down, click, pointer up). “


Continue reading below

It is also explained like this:

“The duration of the event is supposed to be the time between the date and time of the event material and when the next painting is done after the event has been handled.

But if the event does not cause an update, the duration will be the time between the hardware timestamp of the event and when we are sure it will not cause an update.

Two approaches to the interaction latency metric explains that Chrome engineers are exploring two approaches to measure interaction latency:

  1. Maximum duration of the event
  2. Total duration of the event

Maximum duration of the event

An interaction is made up of several events of varying lengths. This measurement is based on the longest duration of a group.

Total duration of the event

This is the sum of all the durations of the event.

Is FID likely to disappear?

It’s possible that FID will remain as part of Core Web Vitals, but what’s the point if a site ever scores 100%?


Continue reading below

For this reason, it is not unreasonable to assume that FID will disappear in the relatively near future.

The Chrome team is seeking feedback on different approaches to measure interaction latency. Now is the time to speak.


HTTPArchive Web Almanac: CMS

Desired opinion: an experimental reactivity metric

Towards a better responsiveness metric