Abstract
Institutional theories and resourceβbased views have suggested that, although they appear similar externally, standardized management systems may be implemented very differently in different organizations. This variability in implementation may be responsible for the heterogeneous performance of these standardized management systems. The current literature on the environmental impacts of ISO 14001 certification has largely neglected this phenomenon. Drawing on our survey of all US 14001 certificate holders, this study finds that great variability does exist in facilities' implementation of ISO 14001 standards. This heterogeneity has a significant impact on the linkage between ISO 14001 certification and facilities' environmental performance. In particular, we find that facilities that integrate ISO 14001 standards into their daily operations are more likely to report improvements in environmental performance. Environmental improvements are also more likely to occur in facilities that include performance management elements in their ISO 14001 standards. Furthermore, both types of facility are more likely to report that ISO certification contributes to this improvement. Neglecting the heterogeneity in facilities' implementation of ISO 14001 standards may explain the instability of findings from the empirical literature investigating the impacts of ISO 14001 certification. Theoretically, this paper informs the understanding of heterogeneous organizational behavior under isomorphic pressures. Copyright Β© 2008 John Wiley & Sons, Ltd and ERP Environment.