Effect of department structure on the organizational citizenship behavior–department effectiveness relationship Timothy DeGroot a, ⁎ , Amy L. Brownlee b,1 a Department of Management, Oklahoma State University, 221 BUS, Stillwater, OK 74078-4011, United States b Department of Management, University of Florida, Gainesville, FL 32606, United States Received 22 September 2005; accepted 21 September 2006 Abstract The purpose of this paper is to investigate how the variable of organizational structure is related to organizational citizenship behavior (OCB) and organizational effectiveness within an organizational setting at the department level. Survey data were analyzed from a sample of 101 firms in the U.S., though missing data leaves only 78 complete cases. To avoid common method bias, both supervisors and subordinates provide data for this study. Two competing models are examined: a moderated model versus a mediated model testing the impact of OCB on the structure- department effectiveness relationship. A strong mediated relationship is found while the moderated model is insignificant. Thus, the relationship between structure, measured on an organic–mechanistic scale, and departmental effectiveness is partly driven by OCB. © 2006 Elsevier Inc. All rights reserved. Keywords: Organizational citizenship behavior; Organizational structure; Departmental effectiveness; Contextual performance 1. Introduction Though the majority of research on organizational citizen- ship behavior (OCB) has been conducted at the individual level of analysis, there are theoretical reasons to believe that unit- level outcomes associated with OCB are important too (Ehrhart and Naumann, 2004). In the aggregate, OCB makes for a more effective organization (Organ, 1988), a proposition that is gaining empirical support (e.g., Koys, 2001; Podsakoff et al., 1997). However, the question remains of whether or not the emerging support for the effects of OCB on organizational effectiveness will hold over all sets of organizational circum- stances and environments. Little research has examined the conditions under which high levels of unit-level OCB are likely to form (Ehrhart and Naumann, 2004). For example, the organizational structure of a firm could impede or facilitate the impact of OCB on organizational outcomes (George and Jones, 1997). Thus, an investigation of an organizational condition, such as unit-level structure, should add to our understanding of the effects of OCB on organizational effectiveness. The specific purpose of this study is to examine how an organizational unit's structure, defined as how the tasks, decision-making hierarchy and goals are specified, might influence the relationship between OCB and the unit's effectiveness. The reason for examining this relationship is that two conflicting perspectives (one with structure as an antecedent and the other with structure as a moderator of the OCB-effectiveness relationship) have evolved from and been suggested in previous research and theoretical development (George and Jones, 1997; Podsakoff and MacKenzie, 1997; Van Dyne et al., 1995). Our study is an initial step to examine this disjoint in the literature. We will do this by first discussing the evolution of OCB and its dimensionality, then review the literature on OCB and its effects on the macro- level variables of organizational effectiveness and structure. Two competing models that could explain the relationships among this study's variables are outlined and empirically tested. We then discuss the implications of our findings in this under researched area. Journal of Business Research 59 (2006) 1116 – 1123 ⁎ Corresponding author. Tel.: +1 405 744 4049; fax: +1 405 744 5180. E-mail addresses: tim.degroot@okstate.edu (T. DeGroot), amy.brownlee@cba.ufl.edu (A.L. Brownlee). 1 Tel.: +1 352 336 6264. 0148-2963/$ - see front matter © 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.jbusres.2006.09.020