During our study of the different types of organization structure we covered all the three of them viz – Functional, Matrix (which includes Weak Matrix, Balanced Matrix and Strong Matrix) as well as Projectized Organization Structures, however there is a fourth type as well known as Composite Organization Structure which can be found in some of the PMP books.
Composite organization structure, simply put, is basically a combination of all three organization structures. But how is that possible you may ask.
But come to think of it, this is quite simple. Within an organization there could be certain projects that are being managed following the Balanced Matrix Organization Structure while others could be following the Projectized Organization Structure. A new project may popup where it is beneficial for the team to follow the Functional Organization Structure. So within the same organization we can see all structures being used and this is by definition a Composite organization.
It should be noted here that in a functional organization all projects follow the functional organization structure. Almost all modern organizations follow the composite organization structure.
And while we are at it, make sure you do not confuse this with Tight Matrix