CRO Glossary
Copy Testing
Experimenting with wording, headlines, and messaging to see which language most effectively drives user action.
Copy testing focuses specifically on the words on a page or in a message — headlines, button labels, value propositions, error messages — rather than layout, color, or structure. Because copy is usually cheap and fast to change, it's one of the highest-velocity categories of test a CRO program can run, contributing directly to overall experiment velocity.
Effective copy tests are grounded in a clear hypothesis statement about what psychological lever is being pulled — for instance, testing a headline that leans on social proof ('Join 50,000 marketers') against one that leans on urgency ('Offer ends tonight'), rather than testing wording changes at random. Small wording differences can produce surprisingly large effects, which is part of why copy testing is popular, but it also means results can be fragile and highly context-dependent.
A common gotcha is testing copy in isolation from the audience and channel it will actually be seen in: a headline that wins with paid search traffic searching for a specific term may lose with organic homepage visitors who lack that context. Because of this, many teams re-validate strong copy test winners across different traffic sources before rolling them out everywhere, and watch for regression to the mean in follow-up tests of the same idea.
Related terms
Above vs Below Median Split
A segmentation technique that divides users into two groups at the median of a metric to compare high and low engagers.
Qualitative Feedback Loop
A recurring process of collecting and acting on user comments, session recordings, and survey responses to inform test hypotheses.
Experiment Metadata
The structured record of who, what, when, and how for a test — hypothesis, owner, dates, variants, and metrics used to track and audit it.
Pre-Test Analysis
The upfront work of validating traffic, metrics, and baseline data quality before launching an experiment.
Above-the-Fold vs Below-the-Fold Messaging Hierarchy
How the order and prominence of value-proposition messaging is split between the visible screen and the rest of the page.
Experiment Contamination
When a control or variant group is unintentionally exposed to the other condition, corrupting the comparison.
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