It is widely accepted that success in markets is largely derived from a firm’s HR and that
HR are one of the most important resources to generate a firms’ competitive advantage, as
HR practices can be imperfectly imitable for a number of reasons, such as unique historical
conditions, causal ambiguity or social complexity (Barney 1991; Barney and Wright 1998;
Pfeffer 1998). The reflection of this notion in the field of HRM is the growing popularity
and wider recognition of theoretical and empirical research on strategic human resource
management (SHRM), which was defined by Wright and McMahan (1992, p. 298) as: