Scope of attention
In-house employees know the ins and outs of the companies they work for, as their attention is completely devoted to one company and its clients. This expertise enables even the most junior person to bring value to the company.
In an agency, the time spent with clients can vary, and contributions may be project specific. Publicists tend to be generalists, and their company-specific knowledge pales against that of someone in-house.
Variety of work
In-house, the variety of one’s work is limited to one company, while publicists in agencies have their hands full with the campaigns of various clients. The plethora of clients can help newcomers experience many aspects of public relations that come with servicing different accounts, while in-house staffers experience only the strategies that their company employs.