Servant Leadership: A Quantitative Review of Instruments and Related Findings
Although Robert K. Greenleaf's servant leadership philosophy is almost 35 years old, only in the past decade have validated instruments been developed and described in peer reviewed literature. This article provides a review of six instruments that measure constructs related to servant leadership, and summarizes 84 statistical results from 20 quantitative, peer reviewed studies. Keywords: Servant leadership instruments, organizational leadership Among many leadership enthusiasts, the idea of being a servant leader is very appealing. However, the implementation of servant leadership brings to mind a bevy of academic queries. For instance, what is the most commonly accepted definition of servant leadership? Also, how do we know if someone is high or low on servant leadership? Finally, can we empirically confirm or deny the effectiveness of servant leadership? Obviously, servant leadership is a theory that needs measureable components. As such, social scientists are charged with developing and validating instruments that will help us gain a better understanding of servant leadership and its related concepts. SERVANT LEADERSHIP: QUANTITATIVE REVIEW 77 SLTP. 2(2) 76 96 Since the 1970s, servant leadership has been a popular philosophy, but it has generally lacked a testable set of constructs. A step toward a more concrete definition occurred when Spears (1995) put forth his 10 aspects of servant leadership. Consequently, several researchers used his work as a foundation from which they were able to develop various models and instruments related to servant leadership. However, despite the appearance of advanced scholarly evolution on this topic, the current conceptual consensus leaves much to be desired. Therefore, true academic achievement with respect to servant leadership will require movement beyond the prevailing status quo of theoretical disunity (Brown Bryant, 2015) To that end, our readers will benefit from scholarly evidence presented primarily from a two pronged approach. First, this article will provide data related to six major instruments that have been used to measure servant leadership. Next, because "more empirical research of servant leadership is needed at multiple levels of analysis in order to increase construct clarity," (Brown Bryant, 2015, p. 18) the tables in Appendix A provide a summary of the emerging empirical base for servant leadership. These tables reveal scientifically established relationships between servant leadership and a host of individual, dyadic and organizational level variables. It is our hope that this dual combination of information will serve as the impetus for continued academic inquiry in to the concept of servant leadership. Figure 1 provides us with a general sense that interest in servant leadership has multiplied since the year 2000. Despite the large amount of attention that servant leadership has received, there is no widely agreed upon model of servant leadership, and there is no widely used instrument to measure servant leadership. Moreover, we do not believe that a sufficient number of studies exists that would allow for the creation of a meta analysis. This assertion would appear to contradict the work of Hunter and Schmidt (2004) who posit that a minimum of six studies are needed in order to conduct a metaanalysis. To meet that minimum, however, would require that the same independent and dependent variables be used in each of the six studies. Nonetheless, we anxiously await the first meta analysis on servant leadership, and we are optimistic that this review will serve as a catalyst for such erudite work. Figure 1. Rise in Publications on Servant Leadership. Book Publications Dissertations Peer Reviewed Articles 78 GREEN, RODRIGUEZ, WHEELER, AND BAGGERLY HINOJOSA (c) 2015 D. Abbott Turner College of Business. LITERATURE REVIEW Models of Servant Leadership Parris and Peachey (2013) found that many writers use all or part of Greenleaf's (1977) definition as a foundation for discussing servant leadership. "The best test, and difficult to administer, is: Do those served grow as persons? Do they, while being served, become healthier, wiser, freer, more autonomous and more likely themselves to become servants?" (Greenleaf, 1977, p. 6) In addition to Greenleaf's quotation, the two models proposed by Spears (1995, 1998) and Laub (1999) are often used as foundational models of servant leadership. Table 1 provides the constructs posited by Spears and Laub. Table 2 provides the servant leadership constructs created by researchers who have developed instruments over the last decade. Table 1. The Most Frequently Referenced Models of Servant Leadership. Spears (1995, 1998) Listening Empathy Healing Awareness Persuasion Conceptualization Foresight Stewardship Helping people grow Community building Laub (1999) Valuing people Building community Providing leadership Developing people Displaying authenticity Sharing leadership Table 2. Emerging Models of Servant Leadership. Ehrhart (2004) Forming relationships with subordinates Empowering subordinates Helping subordinates grow and succeed Behaving ethically Putting subordinates first Having conceptual skills Creating value for those outside the organization Barbuto and Wheeler (2006) Altruistic calling Wisdom Emotional healing Organizational stewardship Persuasive mapping Liden, Wayne, Zhao and Henderson (2008) Emotional healing Creating value for the community Helping subordinates grow and succeed Conceptual skills Putting subordinates first Behaving ethically Empowering Sendjaya, Sarros and Santora (2008) Voluntary subordination Authentic self Covenantal relationship Responsible morality Transcendental spirituality Transforming influence van Dierendonck and Nuijten (2011) Empowerment Standing back Authenticity Interpersonal acceptance Accountability Humility Courage Stewardship SERVANT LEADERSHIP: QUANTITATIVE REVIEW 79 SLTP. 2(2) 76 96 Measuring Servant Leadership To date, there are six instruments for which a sufficient amount of psychometric development has been reported in the peer reviewed literature. First, Laub's (1999) dissertation provides us with details regarding the robust creation of the Organizational Leadership Assessment. Second, Ehrhart (2004) successfully reveals discriminant validity for his Servant Leadership Scale. Third, Barbuto and Wheeler (2006) provide us with evidence regarding four types of validity (face, convergent, discriminant and predictive) for the Servant Leadership Questionaire; additionally, Mahembe and Engelbrecht (2013) report acceptable reliability scores for this instrument. Fourth, Liden, Wayne, Zhao and Henderson (2008) report empirical data related to face, convergent and predictive validity for their Servant Leadership Scale. Fifth, Sendjaya, Sarros and Santora (2008) reveal face validity and content validity with respect to the Servant Leadership Behavior Scale. Lastly, van Dierendonck and Nuijten (2011) report convergent validity and acceptable reliability scores for the Servant Leadership Survey. Based on these rich forms of empirical evidence, we have elected to include the aforementioned instruments in our review. Table 3 is a listing of these six instruments and their authors. Table 3. Instruments to Measure Servant Leadership. Instrument Author(s) Organizational Leadership Assessment Laub (1999) Servant Leadership Scale Ehrhart (2004) Servant Leadership Questionnaire Barbuto and Wheeler (2006) Servant Leadership Scale Liden, Wayne, Zhao and Henderson (2008) Servant Leadership Behavior Scale Sendjaya, Sarros and Santora (2008) Servant Leadership Survey van Dierendonck and Nuijten (2011) Organizational Leadership Assessment The Organizational Leadership Assessment indicates that it measures six aspects of servant leadership, as shown in Table 4. 80 GREEN, RODRIGUEZ, WHEELER, AND BAGGERLY HINOJOSA (c) 2015 D. Abbott Turner College of Business. Table 4. Dimensions Measured by the Organizational Leadership Assessment. Laub (1999) Valuing people Believing in people Serving other's needs before his or her own Receptive, non judgmental listening Developing people Providing opportunities for learning and growth Modeling appropriate behavior Building up others through encouragement and affirmation Building community Building strong personal relationships Working collaboratively with others Valuing the differences of others Displaying authenticity Being open and accountable to others A willingness to learn from others Maintaining integrity and trust Providing leadership Envisioning the future Taking initiative Clarifying goals Sharing leadership Facilitating a shared vision Sharing power and releasing control Sharing status and promoting others