We can optimize through what we measure. The combination of synthetic measurements and Real User Monitoring (RUM) is key. The synthetic measurements allow us to compare improvements in the exact same test environments, in the same conditions, which means we can compare performance of each version of our code.
We would then test these potential improvements in the field, recording user data which provided insights on their experience as this is what really matters - and wins in a lab environment don’t always translate into wins in the field.
Finally, we focussed on where we could make the biggest difference to the majority of customers so we could make the greatest overall impact. Moving the needle comes down to a combination of smart measurement that guides you to making a difference in the user experience.