Holistic Scoring for Core Web Vitals: Why a Weak Page Can Now Drag Down the Entire Website

The Google Core Update from March 2026 has been complete since April 8. We have analyzed several client websites over the past three weeks and see a clear pattern: sites with poor Core Web Vitals have lost visibility. Sites with good metrics have gained ground.

This isn’t new. What is new is how Google now evaluates these metrics.

We’ve outlined how to respond to the update as a whole and which immediate actions make sense in our Core Update Checklist for SMEs. This post focuses on one aspect that we deliberately left out of that checklist: the technical change in the evaluation logic of Core Web Vitals.

In this post, we explain exactly what has changed. We highlight the three thresholds that SMEs need to keep an eye on. And we provide a brief checklist that allows a marketing manager to assess the status of their own website in just half an hour.

What Core Web Vitals Are and Why They Matter

Core Web Vitals are three metrics that Google uses to evaluate the technical quality of a website. They measure how fast, stable, and usable a page is from the perspective of a real user.

The three metrics are:

• LCP (Largest Contentful Paint): How long does it take for the largest visible element to load? Threshold: under 2.5 seconds.
• INP (Interaction to Next Paint): How quickly does the page respond to clicks and input? Threshold: under 200 milliseconds.
• CLS (Cumulative Layout Shift): How often does the layout shift during loading? Threshold: under 0.1.

These three thresholds have remained unchanged. Nevertheless, many B2B websites lost visibility after the March update. The reason lies in a silent change to the scoring.

The key change: Holistic Scoring

Previously, Google evaluated each page of a website individually. A slow product page had no direct impact on the homepage’s ranking. That has changed.

With the March 2026 Core Update, Google now evaluates Core Web Vitals site-wide. The values of all pages on a domain are factored into an overall score. This is called Holistic Scoring. A single slow product page can thus drag down the entire domain.

Real-world example: For a mechanical engineering firm in Upper Swabia, the homepage had a good LCP of 1.8 seconds. But the 40 product detail pages had values between 4 and 6 seconds. After the update, the homepage’s visibility dropped. The reason wasn’t the content. The reason was the product pages.

The official definition of the three metrics and their thresholds can be found on Google Search Central and on web.dev. Google has documented the rollout of the March 2026 Core Update in the Search Status Dashboard.

How the metrics are measured

Google uses field data from the Chrome User Experience Report (CrUX) for its evaluation. These are real measurements from real users, not lab data. A prerequisite is that a page has enough traffic to generate CrUX data.

For websites with low traffic, Google relies on origin data. These are aggregated values for the entire domain. This is exactly where Holistic Scoring comes into play: sites with limited data per individual page are automatically evaluated site-wide.

Marketing managers need two tools:

• PageSpeed Insights (pagespeed.web.dev): Displays lab and field data for a single URL.
• Search Console: Displays the site-wide status under Extensions → Core Web Vitals.

Important: Search Console groups URLs into clusters. If a cluster is marked as “Poor,” this often affects hundreds of URLs. It is precisely these clusters that are now dragging the domain down.

What specifically changes for SMEs

Based on our experience from recent client projects, the update primarily affects three scenarios:

Case 1: Old WordPress themes with many plugins. Themes from 2020 or 2021 are often not optimized for modern image formats. Plugins add JavaScript that worsens the INP score. At a tax consulting firm, we found 18 active plugins, 11 of which were no longer being updated.

Case 2: TYPO3 websites with large, uncompressed images. Many B2B sites contain PNG or JPG images ranging from 2 to 5 megabytes. Modern formats like WebP or AVIF reduce this to one-fifth. Without this optimization, LCP regularly remains above 3 seconds.

Case 3: Cookie banners and marketing scripts. Tag Manager, Hotjar, LinkedIn Insight Tag, and cookie banners are often loaded simultaneously. Each of these adds milliseconds to the INP. In total, that’s 300 to 500 milliseconds that push the limit.

30-Minute Performance Check for Your Own Website

A marketing manager can assess the performance status of their own website in half an hour. It’s all about the three metrics—LCP, INP, and CLS—not content or rankings:

1. 1. Open Search Console (10 minutes): Under “Extensions → Core Web Vitals,” check how many URL clusters are marked as “Poor” or “Needs Improvement.” Export the list.
2. 2. Run PageSpeed Insights for three key pages (10 minutes): homepage, a product or service page, and a contact page. Note the metrics for the last 28 days.
3. 3. Take stock (10 minutes): Are all three metrics (LCP, INP, CLS) in the green zone? If not, in which cluster are the issues? Are they on individual pages or the entire site?

The result is not a technical audit. It is an assessment that enables a discussion with the development department or a service provider.

What we specifically check in client projects

When we perform a CWV check for a new project, we proceed in this order:

1. 1. Check image formats: Are WebP or AVIF used? Are images delivered responsively? Is lazy loading enabled?
2. 2. Reduce JavaScript: Which scripts run synchronously? Which ones can be deferred or loaded asynchronously? Which ones are unnecessary?
3. 3. Caching and compression: Does the server support Brotli or at least gzip? Are static resources cached long-term?
4. 4. Server response time: Is the Time to First Byte under 800 milliseconds? If not, the hosting is usually the problem.
5. 5. Cookie banner: Is the banner loaded asynchronously? Does it block the initial render?

Experience shows that these five steps cover 80 percent of typical issues. The remaining 20 percent are individual cases that require a technical audit.

What Holistic Scoring Means Strategically

Before the March update, it was acceptable to technically neglect individual sections of a website. An old press release or a slow career portal had no direct impact on the visibility of the main pages.

That is no longer the case. Every URL with poor scores drags down the domain. This has two consequences:

First: Clean up old content. Press releases from 2018, event announcements from 2020, expired job postings. Much of this is no longer up to date technically. If it doesn’t perform, it harms the domain. Either maintain it or remove it.

Second: Performance is a top priority. This issue isn’t solely the IT department’s responsibility. Marketing and management must be involved because investment decisions depend on it. A new theme, new hosting, or a CMS switch often pays off faster than it seems at first glance.

Outlook: What to Watch For

Google continues to develop the set of Core Web Vitals. INP replaced FID as the third Vital in March 2024. The documentation on INP at web.dev shows how Google measures the metric and which optimizations have the greatest impact.

For SMEs, this means: Those with solid Core Web Vitals today are also well-positioned for future updates. The basic principles (fast delivery, low JavaScript load, stable layouts) remain the same, even if Google adds further indicators later.

Conclusion

The March 2026 Core Update did not introduce any new thresholds. The thresholds for LCP, INP, and CLS remain the same as before. What has changed is the scoring logic. Holistic Scoring aggregates a collection of individual pages into a single domain with an overall score.

For SMEs, this means: If you ignore outdated sections of your website, you risk compromising the visibility of the entire domain. A half-hour status check in Search Console is enough to assess the scale of the problem. This leads to the next steps, which are often pragmatic and require manageable effort.

If you’d like to have the status of your website assessed, feel free to contact us. We’ll perform a quick check and give you an honest assessment of whether technical work is needed or if resources would be better spent on content.

FAQ

What are the three Core Web Vitals, and what thresholds will apply in 2026?

The three Core Web Vitals are LCP (Largest Contentful Paint, threshold under 2.5 seconds), INP (Interaction to Next Paint, threshold under 200 milliseconds), and CLS (Cumulative Layout Shift, threshold under 0.1). These thresholds have remained unchanged since March 2026. What has changed is the scoring logic: Google now aggregates the values site-wide instead of per page.

What does Holistic Scoring mean for Core Web Vitals?

Holistic Scoring means that Google aggregates the Core Web Vitals of all pages on a domain into a single score. A single slow product or detail page can thus drag down the entire website’s ranking. Before the March 2026 Core Update, pages were evaluated individually. Since the update, the site-wide score applies.

As a marketing manager, how do you check your website’s status?

Three steps are enough for an initial assessment. First: Open Google Search Console and check the Core Web Vitals report under “Insights.” Second: Open PageSpeed Insights for the homepage, a product page, and the contact page, and review the field data. Third: List which URL clusters are flagged as poor. This allows you to discuss the issue with your development team or service provider.

Which measures improve Core Web Vitals the fastest?

Experience shows that three areas yield the fastest improvements. First: Convert images to modern formats like WebP or AVIF and enable lazy loading. Second: Load marketing and tracking scripts asynchronously instead of synchronously. Third: Check server response time and, if necessary, switch hosting providers if the Time to First Byte exceeds 800 milliseconds.

Sources

• Google Search Central: Core Web Vitals
• web.dev: Core Web Vitals Overview
• Google PageSpeed Insights
• Google Search Status Dashboard

Sources

• Google Search Central – Core Web Vitals
• web.dev – Web Vitals
• Google – Interaction to Next Paint
• Chrome UX Report