What is conversion rate optimization (CRO)?
Conversion rate optimization (CRO) is changing a website's pages so a larger share of visitors take the action each page exists for, such as booking a call, submitting a form or buying, measured as conversions divided by visits.
Cited from the66th.com/glossary/conversion-rate-optimization
How conversion rate optimization works
A conversion rate is the number of visits that end in the action, divided by all visits. If a page gets 2,000 visits a month and 40 of them end in a booked call, its conversion rate is 2%. CRO finds what stops the other visitors, changes it, and measures again.
The causes we look for are plain: the page does not say who the offer is for, the proof sits at the bottom, the button to book is hard to find on a phone, or the form breaks. Analytics and session recordings, which replay how visitors scrolled and clicked, show where people stop.
| Version | Visits | Booked calls | Conversion rate |
|---|---|---|---|
| Before the change | 2,000 | 40 | 2.0% |
| After moving reviews and the booking button to the top of the page | 2,000 | 60 | 3.0% |
Where it shows up
Google Analytics 4 tracks the action a page exists for as a key event. Google's help page About key events defines a key event as an event that measures an action particularly important to the success of the business, and says any event the site collects, such as a form submission, can be marked as one.
GA4's Session key event rate is the percentage of sessions in which a visitor triggered a key event, which makes it the conversion rate GA4 calculates automatically.
What it means for your business
CRO multiplies whatever traffic a page already gets. A page that converts at 3% instead of 2% brings 50% more leads from the same visitors. It also needs enough visits to measure: on a page with 50 visits a month, one extra booking moves the rate by two points, so small pages are judged on recordings and broken actions more than on the rate.
It matters most on the pages that make money: service pages, booking pages, product pages and checkout. A blog post written to answer a question has a different job, which is building authority for the pages that sell. When a page needs a rebuild, that becomes website design work.
Common mistakes
- Changing several things at once and crediting the result to one of them. Change one thing per page, or log every change with its date, so each result has a cause.
- Measuring the wrong action. A view of the contact page is a visit, and a sent form is a lead; mark the form submission or the booked call as the key event in GA4.
- Judging a blog post by its conversion rate. Articles that answer questions build the authority that helps the service pages rank, so judge them by that job.
- Testing headlines before fixing broken forms and buttons. A form that fails on a phone loses every visitor who tries it.
Related terms
Sources: Google Analytics Help, About key events; Google Analytics Help, [GA4] Traffic acquisition report.