Much progress has been made with regard to theory building and application in the field of Strategic Human Resource Management (HRM) since Wright and McMahan’s (1992) critical review. While researchers have increasingly investigated the impact of HR on economic success within the Resource Based view of the firm, and have developed more middle level theories regarding the processes through which HR impacts firm performance, much work still needs to be done. This paper examines how future theorizing in SHRM should explore the concepts of time, cause, and individuals. Such consideration will drive more longitudinal research, more complex causal models, and consideration of multi-level phenomena.