Project management purists insist that subject matter expertise in the environment in which a project is executed isn't a requirement but rather a helpful convenience. Instead, members of the project team should supply specific subject matter expertise (in this case, specific IT knowledge areas). Purists further maintain that the project manager's duties must be limited to identification, development, and managed execution of the project plan--not to provide input to technical solutions. Therefore, a successful project manager would need to be skilled in communication, general management, organisation, behaviour, planning, and so on.
Conversely, many organisations adopting formal project management principles find themselves assigning project management responsibilities to traditional IT project leaders based on their "technical fit" to the project. For example, a database administrator may be assigned to implement a new data warehousing application based on the assumption that the DBA would have the greatest understanding of how to accomplish the project. In this scenario, technical skills take precedence over project management skills.
While both sides offer valid points, it's important to realise that how your organisation's leaders feel about the subject can have a dramatic impact on how projects are pursed and who will be selected to lead them. In other words, the choice of assigning a skilled project manager or a skilled technologist to the role of project leader has a lot to do with the organisation's level of adoption of project management principles, its history of project success, and the personal bias of the organisation's leadership.
Technical projects led by a professional project manager trained in formal project management principles will focus heavily on planning and communication. These projects tend to be well structured with well-defined deliverables and have a clear plan as to what is needed to achieve project goals. The downside is that professional project managers often work outside the organisation's responsibility chain and have a difficult time acquiring or keeping resources. Instead, the professional project manager will spend most of his or her time negotiating with one functional manager after another to get the help they need. In addition, if the project manager doesn't have at least a moderate level of understanding of the technical complexities of their project, delays will likely arise as technical requirements come to light that they didn't understand or even discuss during the planning phases.
Technical projects led by an experienced IT project leader have their own issues. Technologists tend to ignore detailed planning in favor of a solution, which can lead to project delays as stakeholders change requirements and deliverables on a repeated basis. Also, technologists are often task-oriented, which may make it difficult for the technical lead to comprehend the project's larger issues outside of the technical solution.
Notice that I use the label project manager for the person who pursues the formal processes involved in project management and project leader for the technical person who leads a team in the resolution of a technology project. The difference is subtle, but the processes and approach are vastly different.
