B
Evidence Grade B
Graded
accuracy verified by the review judge
Safe to Cite
Current
26%
26% -- false positive rate for A/B tests stopped early (2026)
Stopping A/B tests early can inflate false positive rates to as high as 26% even when using a 5% significance threshold.
- Represents an inflated false positive rate when peeking/stopping tests early under a nominal 5% significance threshold
- Attributed to research by Evan Miller
Attribution:
View source
Lighthouse Research Team
Last verified:
·
How we verify data →
Source verified
Evidence graded
Value
26%
Unit
Percentage
Data Vintage
2026
Entity
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
75
Source Trust
60
Citation Chain
20
Independence
30
Methodology
45
Freshness
95
Source
Evan Miller
Primary
Tier B
https://www.articos.com/blog/ab-testing-sample-size ↗
Source Article
A/B Testing Sample Size: How to Calculate It [Guide]
Original Research
Evan Miller
· Original study ↗
Methodology
Cited research from Evan Miller on statistical significance of early-stopped A/B tests
Methodology documented
Segmentation
Industrymarketing
Cite this stat
Plain Text
A/B tests stopped early: 26% false positive rate. Source: Evan Miller (2026). Via Lighthouse Intelligence -- https://lighthousedata.io/data/early-ab-test-peeking-false-positive-rate
HTML Embed
<blockquote cite="https://lighthousedata.io/data/early-ab-test-peeking-false-positive-rate" style="border-left:3px solid #2563eb;padding:12px 16px;margin:16px 0;font-family:system-ui,sans-serif;background:#f0f4ff;"><strong>26%</strong> -- false positive rate for A/B tests stopped early<br><small>Source: Evan Miller (2026) · <a href="https://lighthousedata.io/data/early-ab-test-peeking-false-positive-rate" target="_blank" rel="noopener">Lighthouse Intelligence</a></small></blockquote>
Share
Related Statistics
Use this data in your work
Copy the citation, embed the widget, or explore thousands more verified marketing statistics -- all free.