The phrase "approach used" refers to the specific way or method that someone takes to do something. It describes the strategy or way of approaching a task or problem. Full definition
I'd love to see that kind of approach used in more games. (gamingpodcast.net)
It describes some of the current products and services and other innovative approaches used by the finance sector to tackle climate change, such as weather derivatives and natural catastrophe bonds. (uncclearn.org)
There are two general treatment approaches used for eating disorders. (psychcentral.com)