Why You Need a Project Manager. Every in-house marketing agency needs a project manager. The agency should be thought of as a company within a company, with its own departments, metrics, and deliverables. There are a lot of moving parts, and things can get confusing when the staff is blended with other areas of the organization. This is why a dedicated project manager is essential. That person can track all of the ongoing projects and provide transparency into the operations of the agency for other company stakeholders. This makes goal-setting easier, and can provide insights into talent gaps that need to be filled, and priorities that need to be adjusted.