<P> Goldratt has been criticized on lack of openness in his theories, an example being him not releasing the algorithm he used for the Optimum Performance Training system . Some view him as unscientific with many of his theories, tools and techniques not being a part of the public domain, rather a part of his own framework of profiting on his ideas . According to Gupta and Snyder (2009), despite being recognized as a genuine management philosophy nowadays, TOC has yet failed to demonstrate its effectiveness in the academic literature and as such, cannot be considered academically worthy enough to be called a widely recognized theory . TOC needs more case studies that prove a connection between implementation and improved financial performance . Nave (2002) argues that TOC does not take employees into account and fails to empower them in the production process . He also states that TOC fails to address unsuccessful policies as constraints . In contrast, Mukherjee and Chatterjee (2007) state that much of the criticism of Goldratt's work has been focused on the lack of rigour in his work, but not of the bottleneck approach, which are two different aspects of the issue . </P> <P> The Theory of Constraints International Certification Organization (TOCICO) is an independent not - for - profit incorporated society that sets exams to ensure a consistent standard of competence . It is overseen by a board of academic and industrial experts . It also hosts an annual international conference . The work presented at these conferences constitutes a core repository of the current knowledge . </P>

Of the seven key principles of the theory of​ constraints which is the first​ principal