ability to realize this. Inherent in this perspective is also the concept ofWt and
equiWnality (Delery and Doty 1996 ) in that diVerent internally consistent con-
Wgurations of distinct resources may provide the source of a sustainable competi-
tive advantage.
Wright et al. ( 1994 ) and Barney and Wright ( 1998 ) investigated the role that
HRM plays in developing a competitive advantage in much detail. Wright et al.
( 1994 : 318 ) concluded that HRM practices themselves cannot be a source of
a sustainable competitive advantage, but that they may play an essential role in
‘developing the sustained competitive advantage through the development of the
human capital pool, and through moderating the relationship between this pool
and sustained competitive advantage by aVecting HR behavior.’ Barney and Wright
( 1998 ) broadened this somewhat narrow view and discussed in more depth how
systems of HRM practices and the administrative HRM function itself could
become sources of sustainable competitive advantage. These authors examined
whether HRM systems and the HRM function meet the criteria set forth by Barney
( 1991 ) and suggested that systems of HRM practices that create synergistic eVects
are indeed a source of a sustainable competitive advantage. These integrated HRM
systems are rare, valuable, and, contrary to physical and organizational capital,
‘diYcult, if not impossible for competitors to identify and copy’ due to the
interrelatedness of the individual HRM practices in the interdependent
HRM system (Barney and Wright 1998 : 40 ). Hence, it is the internalWt between
HRM practices that may provide a signiWcant source of sustainable competitive
advantage.
19.3 The Complexity of Internal Fit
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In the previous section, we presented the foundation of the theory supporting the
importance of internalWt, whether HRM systems in and of themselves (Barney and
Wright 1998 ; Delery and Shaw 2001 ) or the human capital that they create (Wright
et al. 1994 ) are the source of organizational eVectiveness. While it is argued that
strong internalWt of HRM practices can provide a sustainable competitive advan-
tage, in part due to causal ambiguity and social complexity (Barney 1991 ; Barney
and Wright 1998 ), these factors make it very diYcult to specify a priori which sets
of HRM practices actuallyWt together and create the desired ‘invisible capability’
that leads to organizational success (Becker and Huselid 1998 ). There are, thus,
signiWcant challenges, which range from actually designing and implementing
internally consistent HRM systems to empirically specifying and measuring
internalWt. We expand on this in the next section.
388 sven kepes and john e. delery