Core Web Essentials (CWV) is a set of metrics developed by Google to measure the user experience of site visitors.
It gives an idea of how well a web page is performing and helps identify areas that need improvement.
Google offers several metrics for measuring page performance called Web Vitals, which are different from Core Web Vitals. Web Vitals provides an accurate technical view of web page performance.
Basic Web Essentials is a subset of Dynamic Web Elements that measure user experience interactions that are common among site visitors regardless of the type of site they visit.
Specifically, Google defines basic user experience needs as loadingAnd interactionAnd optical stabilization.
All websites should strive for high scores for basic web fundamentals.
to me The Google:
Web Vitals is a Google initiative to provide uniform guidelines for the quality signals necessary to deliver a great user experience on the web.
Site owners don’t have to be performance experts to understand the quality of experience they provide to their users.
The Web Vitals initiative aims to streamline the landscape, helping sites focus on the metrics that matter most, namely Basic web animation. “
Measure user experience with basic web fundamentals
The following three metrics measure the quality of a site visitor’s user experience:
- Biggest fee guaranteed: measures the perceived page loading speed and represents the amount of time it takes to load the largest block of content (text or image).
- The first input delay: measures the amount of delay from when a site visitor first interacts with the page to the moment the browser can respond to the interaction
- Shift in cumulative planning: measures the stability of a web page as it downloads, and provides feedback on how much the page layout has changed.
Google explains why these three metrics in particular are important:
Google believes that “core web vitality” is essential to all web experiences.
As a result, it is committed to featuring these scales in all of its popular tools..”
Related: Googler explains usability factors and UX ranking
Two basic web vitals
Google offers two types of “basic web vitality” metrics: field data and lab data.
Field data is the “basic web fundamentals” measurements taken from site visitors to web pages. Measurements are taken in site visitors using the Chrome browser who have chosen to send anonymous user experience data to Google.
User experience data creates a file Chrome user experience report (Crocs).
It does not include page-level data until you have at least 1,000 monthly visits to that page.
You can find field data collected as part of the Chrome user experience report using Google’s PageSpeed Insights tool.
The Search Console also displays field data, reported in a way that makes it easy to view URLs aggregated by the three Core Web Vitals metrics.
The Data Studio CrUX dashboard visualizes CrUX data (More information here).
Lab data consists of simulated Core Web Vitals results.
The reports generated by Lab Data are intended to receive diagnostic information to improve web page speed results.
Because there is a slight variance each time a test is run, many people will run at least three tests and then average the result.
Core Web Vitals lab data results are also available through the PageSpeed Insights tool, as well as any other third-party tool that uses the Chrome Lighthouse tool.
A headless Chrome bot is sent to a webpage to download and simulate data.
The Lighthouse tool applies synthetic throttling to simulate a mobile device downloading a webpage on a mobile connection.
This is how lab data is simulated Works:
These exact numbers are specified in the Lighthouse constants and are used as the default throttle in Lighthouse.
It accounts for roughly the bottom 25% of 4G connections and the top 25% of 3G connections (at Lighthouse this configuration is currently called “Slow 4G” but used to be called “Fast 3G”).
This preset is identical to WebPageTest’s “Mobile 3G – Fast” and, because of the lower latency, is slightly faster on some pages than WebPageTest’s “4G” preset. “
There are four types of network throttling simulations for those interested in the details of throttling.
1. Simulated throttling. This is what the Lighthouse tool is for.
2. Choke application. This is known as request-level throttling but is referred to as implemented throttling in Chrome dev tools. According to the documentation, this bottleneck is not accurate, so the Lighthouse algorithm makes up for it.
3. Throttling at the proxy level. This does not affect UDP and is therefore not ideal.
How to measure dynamic web fundamentals
As mentioned, Field Data is Core Web Vitals metrics collected from site visitors.
Google Search Console provides Chrome User Experience (CrUX) report data.
PageSpeed Insights also provides CrUX field data.
PageSpeed Insights and Chrome Dev Tools (under the Audit panel) provide lab data that simulates “Core Web Vitals”.
Third-party metrics that use Chrome Lighthouse also provide Core Web Vitals Lab data.
A partial list of free and essentially free third-party speed test tools:
- Web page test.
- HTTPArchive BigQuery.
- scribe (Free and paid versions).
- Lighthouse keeper (page performance monitoring tool).
- Speed Vitals (Free and paid versions).
Related: Making user experience and search engine optimization work together
What about other page speed user experience metrics?
While basic web vitality is important, it is not Just User experience metrics to analyze.
An expanded set of metrics called Web Vitals is available through tools such as PageSpeed Insights.
Google recently announced a new metric called Engagement with Next Paint.
Engagement with Next Paint is a metric that measures how long it takes to interact with the entire webpage, which Google refers to as, General interaction latency.
Source: Chromium blog
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