Job descriptions are written to fill a position.

That sounds obvious, but it’s worth thinking about for a moment. The document exists to define a container: a set of responsibilities, a level, or a function. Something the organization needs covered.

What it doesn’t describe is the person who’s going to do it. How they think, or what they’re good at that won’t show up until month four, or the way they handle situations.

Two people can read the same job description, accept the same offer, and spend the next two years doing fundamentally different work. Not because one is ignoring the description, but because people bring themselves into roles, and no two people bring the same thing.

Organizations write job descriptions as if the role is the work. But the role is just the frame. What goes inside it depends entirely on who walks through the door.