What is CRO (conversion rate optimisation)?
How does CRO work?
CRO starts with a question, not a change. Where do visitors drop out? Why? Analytics shows where. Research with customers suggests why. Then you form a hypothesis and test it, usually with an A/B test.
A hypothesis is a stated reason a change should help. "Shoppers hesitate because delivery costs appear late, so we will show them earlier" is a hypothesis. "Let's try a green button" is not.
The measure is the conversion rate. Always check what it divides by. Shops usually mean orders divided by sessions. Ad platforms may divide by something else.
The page people land on matters most for paid traffic. See landing page.
How do you know a CRO test worked?
Two checks. First, was the difference statistically significant, meaning unlikely to be chance alone? Second, was it large enough to matter? A test can only detect effects above its minimum detectable effect. On a small site, that threshold can be bigger than any lift you could realistically get. Say so before the test, not after.
For ZFD: We run CRO audits and put the changes live ourselves. See our CRO service. The tools and test conditions are covered in ecommerce CRO testing. The same logic applies to ads: creative testing framework.
Easily confused with
CRO vs Conversion rate
The number. CRO is the work of improving it.
CRO vs A/B testing
One method inside CRO. CRO also includes research and analysis.
CRO vs Ad optimisation
Changing campaigns to get better ad results. CRO changes the site.
Buzzword alert
"We'll optimise your conversion rate."
Usually means: a list of changes will be made to the site.
Ask: Which hypothesis was each change based on, and what did the test show?
"Quick wins."
Usually means: changes shipped without a test.
Ask: How will we know each one helped?
"Best-practice CRO."
Usually means: copying what other shops do.
Ask: What evidence from our own visitors supports it?
FAQ
Is CRO the same as A/B testing?
No. A/B testing is one tool. CRO also uses analytics and research to decide what to test.
Can small shops do CRO?
Yes, but not every idea can be tested with a clean A/B test. Research and analysis still help.
Does CRO promise more sales?
No. It is a method for finding out what helps. Any change can win, lose or show nothing.
Sources
Let’s find what’s actually working.
Next step. Traffic is half the job. See our conversion rate optimisation service.