2.1 INTRODUCTIONThe first chapter of this thesis indicated organizational commitment (OC) as a means of improving a wide range of positive organizational outcomes and solving problems of turnover and 'absenteeism. It is essential to have a thorough understanding of the overall concept of CO. Therefore, the main objective of this chapter is to provide a review of CO based on a thorough search of the existing literature. This chapter begins with the theoretical context of CO and its definition in today's world. Different approaches to OC are then discussed and the three-component model will be presented in detail. This chapter progresses towards the assessment of CO in the construction industry based on the existing literature. Finally, a summary is provided at the end of this chapter.2.2 CONTEXT AND DEFINITION OF ORGANIZATIONAL COMMITMENT (OC)Commitment is a multi-foci concept. We find commitment to professional associations, the union, work teams as well as commitment to the family, the State or religion, projects, values ​​or career (Reichers, 1985; Baruch, 1998 ; Meyer & Herscovitch, 2001; OC is one of the five forms of work engagement indicated by Morrow (1983) and has been conceptualized in different constructs, definitions and interpretations to better understand the intensity and stability of an employee's dedication to the organization (Cohen, 2007; Singh and Venugopal, 2008). The first attempt to conceptualize commitment was Becker's (1960) side bet theory. He argued that an individual becomes involved in an organization because of hidden investments. The threat of losing these investments, as well as the perceived lack of alternatives to replace or compensate for the medium of paper, are essential to undertaking project tasks to achieve the objectives. For the QS, achieving goals within the work group creates a positive influence for being a member of the group. Therefore, QS is likely to gain or maintain group membership (Chiu & Ng, 2013). In order to achieve the desired attitudinal and behavioral changes among employees, it is essential to understand the objectives, expectations, and goals of the organization and the employees (Mohyin, Dainty, & Carrillo, 2009). Failure to understand what employees demand and expect from the employment relationship will often result in a deterioration of commitment and loyalty and thus increase employee turnover (Loosemore et al., 2003). This reflects the need to study the background of CO among QSs, examining QSs who work in different consulting and construction companies to fill the knowledge gaps.