CRO Glossary
Ramp-Up
Gradually increasing the percentage of traffic exposed to a new variant rather than launching it to 100% of users at once.
Ramp-up is a risk-management technique where a new experience is rolled out to a small slice of traffic first (say 1-5%), monitored for problems, and then gradually increased toward full traffic allocation if guardrails hold. It's especially common when shipping a change via a feature flag, since flags make it trivial to dial exposure up or down without a new deploy.
The main purpose is to limit blast radius: if a variant has a bug, a broken checkout step, or an unexpectedly severe negative effect on a guardrail metric, catching it at 2% of traffic is far cheaper than discovering it at 100%. Ramp-up is also used after a test declares a winner, to de-risk the full rollout even after the statistical decision has already been made.
A subtlety worth watching for is that a fast, uneven ramp-up schedule can itself introduce statistical noise or timing confounds into an analysis if the traffic split changes mid-experiment — for this reason many teams keep allocation fixed for the official test period and only ramp up after the test has concluded and a decision has been made.
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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