WriterzRoom does not split traffic. Exposures and conversions are entered or imported from the channel that served them; what the Experiment Lab owns is the decision, not the delivery.
The verdict
Each experiment needs exactly one control and at least one challenger. The evaluation runs a pooled two-proportion z-test and returns one of four verdicts:inconclusive and insufficient_data are kept separate on purpose: the first means keep collecting, the second means the sample cannot support the question yet.
Three guards
- Normal-approximation validity. Rather than an arbitrary impressions floor, the test requires at least 5 expected conversions and 5 expected non-conversions per arm under the pooled rate. Below that no p-value is reported, because one would not mean what it claims to.
- Multiple comparisons. Testing several challengers against one control inflates the false-positive rate, so the threshold is Bonferroni-corrected by the number of challengers. Adding a fifth headline makes winning harder, not easier.
- Direction. The p-value is two-sided, so a variant that performs significantly worse is never reported as a winner.
Promotion
A concluded experiment freezes its verdict, whatever it is. An inconclusive result is worth keeping: it is the record that stops the same hypothesis being re-run and read hopefully next quarter. Only an experiment that established a winner can be promoted into a pattern. Promotion is refused outright otherwise, with the verdict and its reason — a warning would be something to click through, and the result would be a coin flip becoming a house style rule nobody can trace. A promoted pattern carries its evidence forward — sample size and p-value — and can be scoped to verticals, channels, or audiences. Active patterns are given to the writer on generations that fall within their scope, labelled as this account’s measured house style rather than general best practice; an empty scope applies everywhere. Retiring a pattern deactivates it rather than deleting it, so it stops applying while work already written under it stays traceable.Audiences
Scope a promoted pattern to the audience it was proven on.
Campaigns
Group an experiment’s pieces under the initiative that ran it.