This study examines the simultaneous effect of leader-member exchange (LMX) and coworker exchange (CWX) on employees’ helping behavior. It proposes that the congruence and incongruence of LMX and CWX have both a linear and curvilinear relationship with helping behavior. Hypotheses were tested on a final sample of 881 participants at hospitals in Taiwan. After controlling for relevant variables, results of a polynomial regression and response surface methodology indicate a positive linear relationship between the simultaneous effect of the congruence of LMX and CWX and employees’ helping behavior, but do not confirm a curvilinear relationship, whereas the simultaneous effect of the incongruence of LMX and CWX has a curvilinear relationship with employees’ helping behavior but not a linear relationship. The theoretical and practical implications, strengths and limitations, and directions for future research are discussed.
