A position description is one way to view an employee.

Another way is to consider their personal, professional, and organizational goals.

One way will give you a narrow perspective, and the other provides wider and deeper insights.

If you require a replaceable unit in a system, stick to the position description. However, if your aim is to foster future talent, opt for the latter approach.

The most effective way is to consider the position description within the context of where they see themselves now and where they want to go.