Alexian Chiavegato 2021-07-09

9 things you need to know about Core Web Vitals


Core Web Vitals have been one of Google's more transparent updates to the search ranking process. This means publishers have had the time and information to prepare in advance. But, SEO is a complicated beast. Despite aiming to simplify what publishers need to deliver in terms of the mobile experience, there are some things that publishers need to take into account when planning their Core Web Vital upgrades. Here are 9 things that every publisher should know about Core Web Vitals, even if you feel ready and prepared for the update. 

1. The deployment has been delayed

When it was announced, Google said that Core Web Vitals would become an experience ranking factor in May 2021. Perhaps to refine their system, give publishers more time to prepare, or a combination of both, Google is delaying the implementation date. Core Web Vitals won't become a direct ranking factor until mid-June 2021. This gives publishers more time to implement best practices in advance so they don't suffer a major traffic dip when the core update makes this ranking factor live. 

2. AMP and PWAs are not guaranteed to score high 

AMP pages and PWAs are built with many of the same goals as Core Web Vitals. They both aim to serve content to readers quickly and smoothly. Many publishers have asked if PWA and AMP will be scored using Core Web Vitals or if just using AMP or PWAs are enough to guarantee a 'good' score across the board. To answer that, AMP versions and PWA pages are subject to Core Web Vital scoring, and although they are likely to do well by design, it is not guaranteed they will pass. Check our guide to Core Web Vitals and AMP and make sure these pages are included in your optimization strategies. 

3. All metrics are scored the same, regardless of device or connection 

It's a common question that raises an issue of fairness. But there are no considerations made to publishers that have audiences with low-spec devices, or low-quality connections. If your main audience comes from a country with a predominantly 3G connection, or from low-spec devices, you have to meet the same standards as everyone else. These publishers will have to implement a leaner process to score high with Core Web Vitals. 

4. Matching search intent will still beat experience signals 

It's possible to be swept away with the need to optimize the mobile experience, but content is still king. Google has explicitly stated that pages that match the user's search intent can rank higher than pages with better Core Web Vital scores. Corre web vitals remain one element of the page experience, which is also just one element of the full ranking criteria. 

5. A fast page may score poorly 

Because core web vitals correspond to very specific elements of the loading process, pages that are considered 'fast' to tools like Page Speed ​​Insights can still get low scores. Making sure pages are fast where it matters. A page can be considered fast, but if it doesn't prioritize the first contentful paint, or has a large amount of layout shift, it will still score poorly in core web vital scoring. 

6. Lighthouse and The Search Console 

Core Web Vitals report can show different results There are two ways to measure Core Web Vitals. Using Field Data or Lab Data. Field data is a real report on how a particular URL performed, and represents anonymized performance data from users in the real-world on a variety of devices and network conditions. Lab data uses the simulated loading of a page on a single device with a fixed set of network conditions. 

7. Core web vitals are subject to change 

Recently, Google amended how they measured cumulative layout shifts. Previously, CLS would add up every shift throughout a session. This means that the longer the session, the more likely it becomes to get a high CLS score. Even if the shifts have very little effect on the overall quality of the session, or are barely even noticed through a long session, can add up to a 'poor' rating. This is the unintended consequence that Google is trying to refine out of the process. You can read our deep dive into the exact changes here

8. Lighthouse measures Core Web Vitals and more 

Google's Lighthouse scoring tool will measure all Core web vitals, but it also measures: 

  • First Contentful Paint 
  • Speed ​​Index 
  • Time to Interactive 
  • First Meaningful Paint 
  • First CPU Idle 
  • Largest Contentful Paint 
  • Total Blocking Time 

9. Field data is based on the last 28-days of data in Chrome User Experience Report 

This means it can take a while for the updates you make to be reflected in your scores. So, you may not see instant impacts, but this doesn't mean these were not positive changes. 
Hopefully these small features of Core Web Vitals will help you understand the metrics better and improve your scores. 

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