A unique number assigned to each payroll processing entity that is used to divide your company into groups for payroll processing. Your company can have several PSIDs, depending on its size and complexity. PSIDs control features such as the valid frequencies for paying employees labour distribution defaults, and employee name formats.
The PSID can represent your company's organizational structure. However, it isn't a requirement that the PSID represent reporting or organizational structure.
The PSID combined with the district ID makes up the payroll ID, which is a nationally unique identifier that consist of up to 6 characters.