Many employee resource groups are formed because people from marginalized groups ask their employers for setting up a network that would support their needs on a local level (bottom-up). The “think globally, act locally” approach works best when there are employees who care about diversity and inclusion and are supported by their leaders and senior managers.
In many organizations there is diversity and inclusion strategy and an overal strategy for ERGs which includes the business case and guidelines (top-down). The organization can either start ERGs or invites groups of employees to apply for ERG status.
For more information see ERG Playbook >>