There are many ways companies measure the effectiveness of their push messages (incremental lift).
Some will have a larger radial geofence around a given area (200-500m) to attract users via push to a surrounding area. They will then have a smaller (50m) radial geofence around the center of a store location or a polygonal geofence around the store. Gimbal does have a solution to help retailers build this out. One option is to do some logic on the back-end to determine if a customer receives the push and entered the smaller 'inner' geofence and dwelled for X period of time. Others will use this and/or coupon redemption codes. Coupon redemptions are the most accurate way to measure lift as you can count the revenue dollars and not just visits.