In industrial and organizational psychology, organizational citizenship behavior (OCB) is a person's voluntary commitment within an organization or company that is not part of his or her contractual tasks. Organizational citizenship behavior has been studied since the late 1970s. Over the past three decades, interest in these behaviors has increased substantially. Organizational behavior has been linked to overall organizational effectiveness, thus these types of employee behaviors have important consequences in the workplace. Dennis Organ is generally considered the father of OCB. Organ expanded upon Katz's (1964) original work. Definition of the concept Organ (1988) defines OCB as "individual behavior that is discretionary, not directly or explicitly recognized by the formal reward system, and that in the aggregate promotes the effective functioning of the organization". Organ's definition of OCB includes three critical aspects that are central to this construct: First, OCBs are thought of as discretionary behaviors, which are not part of the job description, and are performed by the employee as a result of personal choice. Second, OCBs go above and beyond that which is an enforceable requirement of the job description. Finally, OCBs contribute positively to overall organizational effectiveness. At the same time, Organ's (1988) definition of OCB has generated a great deal of criticism. The very nature of the construct makes it difficult to operationally define. Critics started questioning whether or not OCBs, as defined by Organ, were discretionary in nature. Organ (1997), in response to criticisms, notes that since his original definition, jobs have moved away from a clearly defined set of tasks and responsibilities and have evolved into much more ambiguous roles. Without a defined role, it quickly becomes difficult to define what is discretionary. Similar constructs Contextual performance OCB has often been compared to contextual performance. Similarly to OCB, this concept emerged in response to the realization that only looking at job specific work behaviors ignored a significant portion of the job domain. Originally, experts in this field focused only on activities that directly supported the output of the organization. As the job market became more aggressive, it became necessary for employees to go above and beyond that which is formally required by the job description in order to remain competitive. Contextual performance is defined as non-task related work behaviors and activities that contribute to the social and psychological aspects of the organization. Contextual performance consists of four elements: persistence of enthusiasm, assistance to others,