A/B testing impact WordPress sites
Performance impact by ab_testing provider.
1
At a glance the headline numbers for A/B testing impact
Performance impact by ab_testing provider.
2
Providers ranked
After min-sites filter
7,623
Sites in sample
Combined across all items
2.6s
Best LCP (p75)
VWO
The State of Web Vitals · October 2026 · WordPress sites (63,295) · all devices field datacorewebvitals.io/state-of-cwv
2
The ranking sorted by LCP at p75, fastest first
| # | Provider | LCP p75 | Passing | Sites | |
|---|---|---|---|---|---|
| 1 | VWO | 2.6s | 73.0% | 92 | |
| 2 | Google Optimize | 2.7s | 70.1% | 7,531 |
The State of Web Vitals · October 2026 · WordPress sites (63,295) · all devices field datacorewebvitals.io/state-of-cwv
3
Passing LCP per provider which group passes the LCP most often
ProviderSitesPassing LCPp75
Convert 0% 25 2.5s
VWO 0.1% 92 2.6s
LaunchDarkly 0% 18 2.6s
Google Optimize 11.9% 7,531 2.7s
Kameleoon 0% 6 2.6s
Optimizely 0% 9 2.9s
Good Needs Improvement Poor Sorted best-passing first · median colored by its own rating · pass = good LCP (2.5s at p75) · one value per site
The State of Web Vitals · October 2026 · WordPress sites (63,295) · all devices field datacorewebvitals.io/state-of-cwv
4
All five vitals at once the whole category without toggling - cell is the pass rate, small number the p75
LCP
INP
CLS
FCP
TTFB
Google Optimize 11.9%
702.7s
98100ms
870.05
592.3s
311.8s
VWO 0.1%
732.6s
95123ms
930.03
592.3s
331.7s
Convert 0%
752.5s
100147ms
790.06
712.0s
461.7s
LaunchDarkly 0%
712.6s
77193ms
780.09
562.5s
252.0s
Optimizely 0%
562.9s
78163ms
780.10
672.5s
441.6s
Kameleoon 0%
672.6s
83155ms
670.10
172.4s
01.8s
60%95%+ passing Cell: pass rate, small number = p75 · faded rows: under 100 sites
One row per provider, one column per vital - the cell is the share of sites passing, the small number the p75. No toggling needed to see where the category actually differs.
The State of Web Vitals · October 2026 · WordPress sites (63,295) · all devices field datacorewebvitals.io/state-of-cwv
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