How long should an A/B test run?
How long an A/B test should run, planned before it starts, in whole weeks, with the smallest change your traffic can detect worked out for 2, 4 and 8 weeks.
Goal
A goal is an outcome you decide to count, such as a purchase, a sign-up or a booked demo, so reports can show who reached it.
An event records that something happened. A goal says which of those things count as success. Setting goals is what turns traffic reports into business reports: instead of pageviews per channel, you see sign-ups or orders per channel.
Most sites need two or three goals. A shop has the purchase; a software company has the sign-up and the paid plan; almost every business has a sign that someone is close to buying, such as a pricing page view.
In MIRA FIVE
A goal is an action with a role. Purchase decides who counts as a buyer and carries the revenue, read from the event’s revenue property or from a property the goal names, and shown per currency. Conversion covers other successes, such as a sign-up or a lead. Intent marks a sign that someone wants to buy, and the people who show it appear as high intent in People. Each goal has a page: who reached it, where they first came from and how long they took to convert. From there, “Test a change that moves this goal” opens a new A/B test decided by that goal.
Example
The Acme Shop’s goal “Order paid” counted 138 buyers and €21,582 in the last 30 days, a 13% conversion rate, with a median of 10 days from first visit to purchase.