While testing is a critical part of conversion optimization to make sure we actually made things better and by how much, it’s also the tip of the iceberg of the full CRO picture. Testing tools are affordable (even free), and increasingly easier to use – so pretty much any idiot can set up and run A/B tests. This is not where the difficulty lies. The hard part is testing the right things, and having the right treatment. The success of your testing program is a sum of these two: number of tests run (volume) and percentage of tests that provide a win. Those two add up to indicate execution velocity. Add average sample size and impact per successful experiment, and you get an idea of total business impact.