When approving the launch of an employee led ERG, should the group be limited to one region even if the membership appears needed globally? What reasons would make that a better choice?

For an ERG to be effective, it'd be best to limit its size and reach in order to create controllable impact. The same ERG could be represented in different geo locations, and meet as a big group on an infrequent basis. E.g. GenZ ERG, where each region could create one with similar culture and time zone, and meet other regions' GenZ ERG at a global level on a yearly basis.  

I think it depends on your ERG and overall culture and operating norms, whether employee groups tend to collaborate and communicate locally, regionally or globally.  If you culture permits, I would recommend global membership, for maximum inclusivity. You can work around logistical issues, for example, meetings could be scheduled a different times on a rolling basis, to account for time zone differences.

We have regional ERGs, however there are connections between the ERGs globally. We also have one ERG/BG that is Global. Sometimes having a global ERG can be challenging logistically with time zones. We do look at providing connections between the ERGs regardless of where they are located. Sometimes the ERGs in the different region will co-sponsor an event.