B
Evidence Grade B
Graded
accuracy verified by the review judge
Safe to Cite
Recent
85%
85% -- additional visitors required for mSPRT sequential testing (Optimizely, Netflix) (2025)
Always-valid inference (mSPRT) needs roughly 85% more visitors than a fixed-sample test to reach the same confidence.
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Lighthouse Research Team
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Source verified
Evidence graded
Value
85%
Unit
Percentage
Data Vintage
2025
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
Analytics-Toolkit
Primary
Tier B
https://kirro.io/sequential-testing ↗
Source Article
Sequential testing in A/B tests explained
Sequential testing lets you check A/B testing results as data comes in. Without getting tricked by random noise. Instead of waiting for a pre-set end date, you check at planned intervals. The math accounts for the extra looking.
If the difference between versions is clearly big (or clearly zero), yo…
Original Research
Analytics-Toolkit
· Original study ↗
Methodology
Always-valid inference (mSPRT) vs fixed-sample test, per Analytics-Toolkit
Methodology documented
Segmentation
Industrymarketing
Cite this stat
Plain Text
mSPRT sequential testing (Optimizely, Netflix): 85% additional visitors required. Source: Analytics-Toolkit (2025). Via Lighthouse Intelligence -- https://lighthousedata.io/data/msprt-visitors-overhead
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<blockquote cite="https://lighthousedata.io/data/msprt-visitors-overhead" style="border-left:3px solid #2563eb;padding:12px 16px;margin:16px 0;font-family:system-ui,sans-serif;background:#f0f4ff;"><strong>85%</strong> -- additional visitors required for mSPRT sequential testing (Optimizely, Netflix)<br><small>Source: Analytics-Toolkit (2025) · <a href="https://lighthousedata.io/data/msprt-visitors-overhead" target="_blank" rel="noopener">Lighthouse Intelligence</a></small></blockquote>
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