Identifiers & Classifiers attributes uniquely identify businesses and describe their organizational classification. Use these attributes to link records across years and segment businesses by type or ownership.

• Historical ID – A unique 15-digit identifier for a historical record, represented as infogroup_id + historical_year + historical_month. This identifier distinguishes a business record within a specific snapshot year and month.
• Infogroup ID – A unique 9-digit identifier for a business location. This identifier persists across years and is used to link records across snapshots
• Place Type – Indicates the type of place based on its role in the organization.
• Work At Home – Indicates the place is a work at home business.