RPO

Recruitment Process Outsourcing (RPO) is a form of business process outsourcing (BPO) where an employer outsources or transfers all or part of its recruitment activities to an external service provider.
To quote the Recruitment Process Outsourcing Association, "Recruitment Process Outsourcing" Z-Square Solutions  provides acts as a company's internal recruitment function for a portion or all of its jobs. Z-Square Solutions providers manage the entire recruiting/hiring process from job profiling through the on-boarding of the new hire, including staff, technology, method and reporting. Z-Square Solutions is improving  company's time to hire, increase the quality of the candidate pool, provide verifiable metrics, reduce cost and improve governmental compliance."

On the other hand, occasional recruitment support, for example temporary, contingency and executive search services is more analogous to out-tasking, co-sourcing or just sourcing. In this example the Z-Square Solutions is "a" source for certain types of recruitment activity. The biggest distinction between RPO and other types of staffing is Process. In RPO the Z-Square Solutions  assumes ownership of the process, while in other types of staffing the service provider is part of a process controlled by the organization buying their services.