what is the difference between ?

Rami I will slightly differ. In PMBOK Guide 4th and 5th Editions, Work Authorization System is no more a part of PMS, but is an Enterprise Environmental Factor. Work Authorization System is not a part of Project Management at all, it is a system residing in the performing organization for their operations and the method, policies and rules applicable can be inherited to any or all of the projects undertaken by that organization.

For Configuration Management, please refer to PMI's Practice Standard for Project Configuration Management, which includes the whole configuration mechanism as well as the Change Management System. This is part of PMS and will be part of any project management plan. If there is no separate Change Management Plan existing in a project, it should form part of an over-riding Configuration Management Plan which additionally includes all Configuration Items (CIs) and their expected behaviour.

Project Management System is a generic system developed by the parent organization or its PMO for guidance of all projects and programs running in that organization, providing guidelines and instructions on how to develop respective project management plans and what should be the components of the same. This also provides guidance on governance mechanism, which should first be established for every project and approved before respective project management plan is developed.

Thanks for your feedback Suhail - I am glad you raised this point because it is important for me as well in order to be sure that my understanding of things is correct.

For everything I mentioned, I referred to PMI PMBOK and I believe in terms of the Project Management system and Configuration MGT System (Page 566 PMBOK) we are on the same page but for the Work Authorization System, this is how PMI defines the Work Authorization System (PMBOK 5th Page 567):

"A subsystem of the overall project management system, .....".

If this is how PMI defines the Work Authorization System but you mentioned that it is not part of PMS then I need to understand what did I oversee because it is important to me for for many reasons.

Can you shed a light on this please - Thanks Suhail.

Rami, principally Work Authorisation System is an operational subject and if at all something is inherited in project management system, it is being inherited from the operations. If we have a work authorisation system for our operational work, that would affect all projects and programs as one of the Enterprise Environmental Factors (EEFs), and this is an internal EEF. Now while we establish a PMS, maybe through a PMO, we take this inheritance from operations, if available, and inject into our PMS as a value-addition. To validate this point, kindly see if Work Authorisation System is shown as an Enterprise Environmental Factor in Chapter 2, Page 29, 7th bullet point under "Enterprise Environment Factors" namely "Company Work Authorisation System". It is not discussed in detail but it is how Company Work Authorisation System is translated into PMS.

Now I have a better understanding there you were talking about the big picture - Thank You Suhail for elaborating. EEF deals with existing systems and culture so yes, I would agree that the Work Authorization System is part of it which is part of the PMS somehow.