B
Evidence Grade B
Graded
accuracy verified by the review judge
Safe to Cite
Recent
20%
20% -- traffic loss severity gap for sites with poor performance scores (December 2025 Google core update) (2025-12)
Sites with poor performance scores experienced 20-30% more severe traffic losses during the December 2025 core update compared to faster competitors with equivalent content quality.
- Reported as a range of 20-30%
Attribution:
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Lighthouse Research Team
Last verified:
·
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Source verified
Evidence graded
Value
20%
Unit
Percentage
Data Vintage
2025-12
Entity
Geography
GB
Evidence Quality
B
Strong, reliable evidence
Sourced from a well-regarded research firm or industry leader with transparent methodology and a reasonably large sample.
Single source - not yet corroborated
Score breakdown
Extraction
50
Source Trust
60
Citation Chain
20
Independence
30
Methodology
45
Freshness
95
Source
365iwebdesign.co.uk
Primary
Tier C
https://www.365iwebdesign.co.uk/news/2026/01/25/what-makes-website-actually-work/ ↗
Source Article
What Makes a Website Actually Work in 2026? | 365i Web Design
You can spot a website that works within seconds. It loads fast. You immediately understand what the business does. There is a clear way to take action. It looks professional without trying too hard.
Most websites fail at least one of these tests. Many fail all of them.
After building websites for o…
Original Research
365iwebdesign.co.uk
· Original study ↗
Methodology
Range 20-30%, midpoint used
Methodology documented
Segmentation
IndustryRetail
RegionGB
RoleAll marketers
Channelmulti-channel
Cite this stat
Plain Text
sites with poor performance scores (December 2025 Google core update): 20% traffic loss severity gap. Source: 365iwebdesign.co.uk (2025-12). Via Lighthouse Intelligence -- https://lighthousedata.io/data/dec2025-update-traffic-loss-slow-sites
HTML Embed
<blockquote cite="https://lighthousedata.io/data/dec2025-update-traffic-loss-slow-sites" style="border-left:3px solid #2563eb;padding:12px 16px;margin:16px 0;font-family:system-ui,sans-serif;background:#f0f4ff;"><strong>20%</strong> -- traffic loss severity gap for sites with poor performance scores (December 2025 Google core update)<br><small>Source: 365iwebdesign.co.uk (2025-12) · <a href="https://lighthousedata.io/data/dec2025-update-traffic-loss-slow-sites" target="_blank" rel="noopener">Lighthouse Intelligence</a></small></blockquote>
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