KnitKnot index
Measurement lab
Our open lab notebook. Every error bar we publish, and every claim we make about our own accuracy, traces back to an experiment written up here — method, numbers, and what we changed because of it.
- Experiment 001
Does our scorer agree with itself?
Feed the identical AI answer to our scoring pipeline repeatedly, with everything pinned. Do we get the same grades?
Result: Baseline pairwise disagreement up to 16.5% on some stages; after fixes, the customer-facing verdict stage reaches 91% pass-pair agreement, with residual disagreement confined to genuinely hedged answers.
- Experiment 002
The placebo backtest: what does our estimator report when nothing happened?
Take a time window in which a customer shipped no changes, pretend a change shipped, and run our own impact estimator. What "effects" does it report?
Result: 95% null interval ≈ ±23pp win-rate on 15-prompt cohorts — the published noise floor.
- Experiment 003
Regression to the mean: how much do "worst" cohorts improve on their own?
Content optimization naturally targets the buyer questions where a brand performs worst. How much do those cohorts improve with no intervention at all?
Result: +19pp apparent win-rate gain from pure mean reversion, with zero real change.
- Experiment 004
CUPED: using each question's own history to shrink the noise floor
The null interval from experiment 002 is ±23pp — too wide to read small cohorts. Can each question's baseline value, used as a covariate, buy the floor down?
Result: 27% narrower error bars for free — and the optimal adjustment coefficient turns out to be the mean-reversion slope from experiment 003.
Ground rules
How the notebook is kept honest.
Anonymized
Customer workspaces are anonymized in every write-up.
Negative results are published
Several intuitive fixes — worked examples, majority voting on open extraction, bigger judge models — measurably did not help or made things worse, and the write-ups say so.
Invalidated claims are retired
When an experiment invalidates something we previously claimed, the claim is retired.
For the plain-language summary of what these experiments mean for how we report, see our methodology.