The answer is you don’t. You can probably figure out if you have a good mechanic by how well your car stays in working order after a repair. But that is as dependent on the quality of the car as it is the mechanic who fixes the problems. Could you ever know that you have a great mechanic? A world class mechanic? The best mechanic? Of course not. You would have to have enough mechanic-knowledge to make that judgment.

So we judge the ability of our mechanic based on un-mechanic criteria: fair price, timely work, and customer service.

It is difficult, perhaps impossible, to measure the competence of a project manager. We speak the same language, have the same certifications, and have similar experience. We have similar success and failure stories. How can the client tell the difference?

The same way we judge our mechanics: fair price, timely work, and client service.

Therefore, the way to differentiate is not to become the most competent or the most skilled project manager. Yes, you must be competent, you must speak the language, and have the certifications, experience, and credentials. You should take pride in continuing your development as a project manager, increasing your skill and experience over time. But you don’t have to aim to be the best project manager.

You must have a fair price, perform timely work (ie underpromise and overdeliver), and provide great customer service.

So if you are looking for a way to grow your career, instead of taking that extra class on project management, consider instead how you can improve your client service.