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RESEARCH REPORT
Ethical Leadership: Meta-Analytic Evidence of Criterion-Related and
Incremental Validity
Thomas W. H. Ng
The University of Hong Kong
Daniel C. Feldman
The University of Georgia
This study examines the criterion-related and incremental validity of ethical leadership (EL) with meta-
analytic data. Across 101 samples published over the last 15 years (N⫽29,620), we observed that EL
demonstrated acceptable criterion-related validity with variables that tap followers’ job attitudes, job perfor-
mance, and evaluations of their leaders. Further, followers’ trust in the leader mediated the relationships of EL
with job attitudes and performance. In terms of incremental validity, we found that EL significantly, albeit
weakly in some cases, predicted task performance, citizenship behavior, and counterproductive work behav-
ior— even after controlling for the effects of such variables as transformational leadership, use of contingent
rewards, management by exception, interactional fairness, and destructive leadership. The article concludes
with a discussion of ways to strengthen the incremental validity of EL.
Keywords: ethical leadership, construct validity, meta-analysis
Due to a series of highly visible, highly public ethical failures by
senior executives (Cappelli, 2009;Carson, 2003;Zona, Minoja, &
Coda, 2013), researchers have started to investigate the nature and
influence of ethical leadership (EL). Brown, Trevino, and Harrison
(2005) define EL as “the demonstration of normatively appropriate
conduct through personal actions and interpersonal relationships,
and the promotion of such conduct to followers through two-way
communication, reinforcement, and decision-making” (p. 120). EL
highlights the importance of being a moral person; ethical leaders
are trustworthy, fair, prudent, and self-disciplined (Riggio, Zhu,
Reina, & Maroosis, 2010). However, EL also entails a moral
manager dimension; ethical leaders proactively attempt to shape
followers’ values by being moral role models, communicating
important ethical values to followers, using rewards and punish-
ments to promote higher ethical standards, and treating followers
with care and concern (Brown & Trevino, 2006;Treviño, Brown,
& Hartman, 2003). Not surprisingly, employees, customers, job
applicants, suppliers, and other stakeholders all react positively to
EL (Mo, Booth, & Wang, 2012;Strobel, Tumasjan, & Welpe,
2010;Tu & Lu, 2013;Zheng, Wang, & Li, 2011).
Despite the rapid growth in EL research, three important gaps
remain. First, while EL has been shown to relate to work outcomes
in individual studies, the criterion-related validity of EL with work
outcomes across different research designs (e.g., level of analysis
and scales to measure EL) and different cultures (e.g., Eastern vs.
Western) has not been comprehensively reviewed. Demonstrating
criterion-related validity of EL is theoretically important here
because it can clarify how far-reaching and how deep the impact of
this construct could be.
The second gap in the literature is also related to criterion-
related validity and concerns the specific psychological process
through which EL elicits these effects. Although both social learn-
ing theory and social exchange theory have helped explain the
general dynamics underlying the positive effects of EL on em-
ployees (Brown & Trevino, 2006), we know much less about the
mediating psychological process through which EL elicits these
effects. Indeed, Brown and Trevino (2006) explicitly call for more
research along these lines. By examining mediating psychological
mechanisms in more detail, especially those that are consistent
with both social learning theory and social exchange theory, we
can gain a better understanding of why, and not only that,EL
positively affects employees in the work place.
Third, it is not yet clear whether positive reactions to EL are
due, at least in part, to the overlap of EL with similar leadership
constructs (S. T. Hunter, 2012). There is certainly prior research
suggesting that EL is different from some other leadership con-
structs (e.g., Brown & Trevino, 2006;Brown et al., 2005). How-
ever, to further bolster EL’s utility in the organizational sciences,
researchers need to show that EL has incremental predictive power
above and beyond these other constructs; demonstrating incremen-
tal predictive power is an important endeavor in applied psychol-
ogy research because it signals the practical value of a theoretical
construct to organizations (Cortina, Goldstein, Payne, Davison, &
Gilliland, 2000;Dudley, Orvis, Lebiecki, & Cortina, 2006;
Lievens & Patterson, 2011).
This article was published Online First November 24, 2014.
Thomas W. H. Ng, Faculty of Business and Economics, The University
of Hong Kong; Daniel C. Feldman, Terry College of Business, The
University of Georgia.
Correspondence concerning this article should be addressed to Thomas
W. H. Ng, The University of Hong Kong, Faculty of Business and Eco-
nomics, Pok Fu Lam, Hong Kong. E-mail: tng@business.hku.hk
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Journal of Applied Psychology © 2014 American Psychological Association
2015, Vol. 100, No. 3, 948–965 0021-9010/15/$12.00 http://dx.doi.org/10.1037/a0038246
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