“…Our previous work has shown an inverse relationship between the presence of regular nursing staff and violent incidents (Bowers, Allan, Simpson, Nijman, & Warren 2005a;Bowers, Nijman, Allan, Simpson, Warren, & Turner 2005c), as has that of others (Chou, Lu, & Mao 2002;Lanza et al 1994), and in surveys of staff or patients larger numbers are often seen as necessary to reduce levels of violence (FaganPryor et al 2003;Kumar, Guite, & Thornicroft 2001). However one other study has also reported a positive association between staffing numbers and patient aggression (Owen et al 1998).…”