```json
{
    "title": "Core Web Vitals and Web Performance Strategy: A Reality Check",
    "url": "https://performancezen.com/2022/04/01/core-web-vitals-and-web-performance-strategy-a-reality-check/",
    "datePublished": "2022-04-01",
    "dateModified": "2026-05-07",
    "language": "en-US",
    "description": "Google's Core Web Vitals initiative has become a larger part of discussions that we have with customers as they begin setting new performance KPIs for 2021-2022. These conversations center on…",
    "author": "spierzchala",
    "publisher": "Performance Zen"
}
```

# Core Web Vitals and Web Performance Strategy: A Reality Check

[Google's Core Web Vitals initiative](https://web.dev/vitals/) has become a larger part of discussions that we have with customers as they begin setting new performance KPIs for 2021-2022. These conversations center on the values generated by Lighthouse, WebPageTest, and Performance Insights testing, as well as the cumulative data collected by CrUX and Akamai mPulse and how to use the collected information to "improve" these numbers.

Google has delayed the implementation of Core Web Vitals into the Page Rank system twice. The initial rollout was scheduled for 2020, but that was delayed as the initial disruption caused by the pandemic saw many sites halt all innovation and improvement efforts until the challenges of a remote work environment could be overcome. The next target date was set for May 2021, but that has been pushed back to June 2021, with a phase-in period that will last until August 2021

Why the emphasis on improving the Core Web Vitals values? The simple reason is that these values will now be used [as a factor in the Google Page Rank algorithm](https://developers.google.com/search/blog/2020/11/timing-for-page-experience). Any input that modifies an organization's SEO efforts immediately draws a great deal of attention as these rankings can have a measurable effect on revenue and engagement, depending on the customer.

While conversations may start with the simple request from customers for guidance around what they can do to improve their Core Web Vitals metrics, what may be missed in these conversations is a discussion of the wider context of what the Core Web Vitals metrics represent.

The best place is to define what the Core Web Vitals are (done by Google) and how the data is collected. The criteria for gathering Core Web Vitals in mPulse is:

> *Visitors who engage with the site and generate Page View or SPA Hard pages and are using recent versions of Chromium-based browsers.*

However, there is a separate definition, the one that affects the Page Rank algorithm. For Page Rank data, the collection criteria gets a substantial refinement:

> *Visitors who engage with the site and generate Page View or SPA Hard pages **who (it is assumed) originated from search engine results (preferably generated by Google)** and are **using the Chrome and Chrome Mobile browsers**.*

There are a number of caveats in both those statements! When described this way, customers may start to ask how relevant these metrics are for driving real-world performance initiatives and whether improving Core Web Vitals metrics will actually drive improvement in business KPIs like conversion, engagement, and revenue.

During conversations with customer, it is also critical to highlight the notable omissions in the collection of Core Web Vitals metrics. Some of these may cause customers to be even more cautious about applying this data.

Google is, however, listening to feedback on the collection of Core Web Vitals. Already there have been changes to the *Cumulative Layout Shift* (**CLS**) collection methodology that allow it [to more accurately reflect long-running pages and SPA sites](https://web.dev/evolving-cls/). This does lead to some optimism that the collection of Core Web Vitals data may evolve over time so that it includes a far broader subset of browsers and customer experiences, reflecting the true reality and complexity of customer interactions on the modern web application.

Exposing the Core Web Vitals metrics to a wider performance audience will lead to customer questions about web performance professionals are using this information to shape performance strategies. Overall, the recommendation thus far is to approach this data with caution and emphasize the current focus these metrics have (*affecting Page Rank results*), the limitations that exist in the data collection (*limited browser support, lack of SPA Soft Navigations, mobile data only from Android*), and the lack of substantial verification that improving Core Web Vitals has a quantifiable positive effect on business KPIs.