At the moment in my company we have only PM, and as we are a small team we know who would fit for the type of project we have, based on our experience.
As our company grows rapidly, we hired a HR manager and he asked me to define career path for our project manager.
I can't figure out when the junior become senior. I could say it's after x projects or x years of experience, but as I'm young I don't believe the experience is the unique factor.
This is always going to be a subjective measure because it is not a binary decision-it is not like an exam that you have either passed or not.
Having said that, in most situations I have come across it is decided through defined (and somewhat arbitrary) combinations of:
It is usually fairly easy to understand if someone is either a Junior or Senior, it is much more difficult to define what makes them one or the other!
It is made even more difficult by the fact that how your organisation might want to measure/judge it which could be different from how another will decide, so it is not really possible to provide meaningful thresholds - your mileage will indeed vary.
"Junior" and "Senior" are relative titles.
Semantically speaking, you would need minimally 2 PMs in order to quantify that one was "Sr" to the other. Comprehensively, you may need 3 or more PMs, since "jr" and "sr" titles define classes, and a population of 2 hardly creates differentiated 'classes'.
E.G. "junior" PMs would often report to the "senior" PM.... not just have a mentorship exchange with the Sr. PM. I hope you can see from the tiny illustration how such titles are really more about your company's organization structure, rather than having to do with an industry-absolute-skill level.
Why must you define "Jr" and "Sr"?
Look to the driver for why such titles are needed. It may reveal a more important matter.
Consider this:
If you would open a Senior PM position in your company what would you put as the requirements for the job description and requirements?
If a junior is near those reqirements you may consider him/her as Senior. Generaly speaking when people get more responsibilities they try to step up to it and also it is a good motivator.
Senior is when you can let them or you trust them to work by his / her own decission. On the other hand when u deal with Junior, you probably need to always monitor his / her act regarding on every work he / she responsible to.
