Resource augmentation is the process of hiring external workers to complement the skills of the current in house staff. The majority of the project would still be done in the house, while some minor roles will be assigned to the external team for support or assistance.
On the other hand, Project outsourcing is the process of transferring the entire project work to an external outsourcing team. The resources, strategy, and output are all done externally with the usage of the devices and facility of the outsourcing team.