Evaluating people’s skills is best done by looking at behaviours rather than knowledge or experience. I’ve had to do this quite a few times over the years—sometimes when I need to set some guidelines on what makes a junior/mid-level/senior developer, but also when I’m constructing a contract in which someone is required to provide skills transfer as well as some kind of product delivery.
The problem with assessing knowledge or experience is two-fold. First, knowledge is difficult to ascertain without some kind of exam, which usually seems inappropriate. Second (more relevantly) knowledge and experience is pretty useless unless it actually turns into actions. And that’s how we get to the point of evaluating by behaviours. It’s what people do that counts, not what they know.
To start the process—say, to set down some criteria for mid-level versus senior developer—I often find it’s helpful to think of two people who we believe embody each classification. That is, someone you believe to comfortably be mid-level and someone who is clearly senior. Then ask: What is the difference between these two people? How do I know X is mid and Y is senior? Think of situations they find themselves in, think of how each would behave (what you see and hear), and then articulate that. That’s what marks them as different from each other.
Then do this for the different traits you are looking for. When thinking about technical skills transfer I might have categories such as “Test-first development”, “Clean code”, “Refactoring” and so on. If I’m looking at career progression I might include “Participation”, “Innovation”, “Business awareness”, and so on.
Additionally, you’ll see (or expect) common patterns. People will use particular skills, such as refactoring, more widely as they gain experience: as an individual initially, helping across the team as they gain experience, coaching other teams at the more senior levels, and perhaps ultimately externally, speaking at events.
Describing how we expect people to behave, rather than what’s in their head or history, provides clarity both for the individuals we’re seeking to help, and also ourselves by forcing us to think clearly.