While temporary, contingency and executive search firms have provided staffing services for many decades, the concept of an employer outsourcing the management and ownership of part or all of their recruiting process wasn't first realized on a consistent basis until the 1970s in Silicon Valley 's highly competitive high-tech labor market. Fast-growing high-tech companies were hard-pressed to locate and hire the technical specialists they required, and so had little choice but to pay large fees to highly specialized external recruiters in order to staff their projects. Over time, companies began to examine how they might reduce the growing expenses of recruitment fees while still hiring hard-to-find technical specialists. Toward this end, companies began to examine the various steps in the recruiting process with an eye toward outsourcing only those portions that they had the greatest difficulty with and that added the greatest value to them. Initial RPO programs typically consisted of companies purchasing lists of potential candidates from RPO vendors. This "search/research" function, as it was called, generated names of competitors' employees for a company and served to augment the pool of potential candidates from which that company could hire.
Over time, as the business, in general, embraced the concept of outsourcing more and more, RPO gained favor among Human Resource management: not only did RPO reduce overhead costs from their budgets but it also helped improve the company's competitive advantage in the labor market. As labor markets became more and more competitive, RPO became more of an acceptable option. Furthermore, through the advent in the 1980's and 1990's of human resources outsourcing (HRO) companies that began taking on the processes associated with benefits, taxes, and payroll, companies began recognizing that recruiting--a significant cost of HR--should also be considered for outsourcing. In the early 2000's more companies began considering the outsourcing of recruitment for major portions of their recruiting need.
There have been fundamental changes in the US labor market that serve to reinforce the use of RPO as well. The labor market has become increasingly dynamic: workers today change employers more often than in previous generations. De-regulated labor markets have also created a shift towards contract and part-time labor and shorter work tenures. These trends increase recruitment activity and may encourage the use of RPO. It should also be noted that even in slower economic times or higher unemployment, RPO is still considered by companies to assist in an increasing need to screen through a larger candidate pool.