Two of the biggest names in background screenings are coming together following a period of slowing demand for their services. Shares of First Advantage (FA -7.64%) are down 7% and shares of Sterling Check (STER 26.05%) are up 25% after the two companies announced plans for an industry-reshaping merger.A tough market for all involvedFirst Advantage and Sterling Check both provide third-party screening and verification services for employers and other users. The uncertain economy and a slowdown in hiring has ...