Introduction
Unions that represent health professionals have become increasingly important in the employment and political landscape of the USA. Nearly 21% of registered nurses (RNs) in the USA were unionised in 2003 (Terlep 2006). In recent years, nursing unions have claimed credit for wage increases across the USA, hospital worker safety improvements, implementation of minimum nurse-to
patient ratios in California, and the introduction of federal minimum staffing legislation in Congress (California Nurses Association 2009). Hundreds of research studies have established that unionised workers in any sector earn more than their non-union counterparts (Lewis 1986), and this finding has been corroborated in studies of nursing employment (Link & Landon 1975, Fottler 1977, Feldman & Scheffler 1982, Bruggink et al. 1985, Hirsch & Schumacher 1998).