Definitively not a "senior level position" guy, but let me give it a try.
There is no such thing as what you are worth.
Let's assume that it is possible to asses your BaseWorthIndex, which would include such factors as your technical skills, people skills, general experience, relevant industry experience, motivation, work ethics, etc. You will notice that even this base index will not be a constant over time (in general, you learn as your career moves forward, but you may also pick up vices), nor will it be the same for all positions for which you are a potential candidate (industry experience and motivation may vary widely from one position to another).
If you want to consider that your TrueWorth is the amount of value you add to your company by direct result of your labor, you have to consider that this is proportional not only on your BaseWorthIndex, but on a number of force multipliers that your employer provides (or fail to provide). Doing the same excellent work for an obscure IT department in some random enterprise, for a high tech big corporation, for a SV startup or for a non profit results in very different outputs, and that more often than not these are out of your control.
In a sense, the employers with bigger multiplier factors want to bring in the best talent, and should pay above average salaries, industry-wise, but it's not required that this extra factor has to be directly proportional to the value added by your position.
If on the other hand, you want to define your TrueWorth in terms of a ratio between your BaseWorthIndex vs average BaseWorthIndex for your industry, you are in similar problems. Being (noticeably) above average means you may command above average salaries, but it does not mean an arithmetic proportion will be calculated; after all, our BaseWorthIndex is a fiction and it would be extremely hard to measure.
Then there is the issue of cost of living. Since as we discussed before, your compensation is not defined in absolute terms but relative to your peers, the issue of how much does it take to make a decent living at your current location comes to play. Take into account also that this is an asymmetric market and that you are always at disadvantage. I have seen more than one good friend and colleague been lured to NYC or SV/SF on the promise of plump returns, only to find out that cost of living lets them in worse conditions that what they had already achieved locally.
There is no such thing as what you are worth.
Let's assume that it is possible to asses your BaseWorthIndex, which would include such factors as your technical skills, people skills, general experience, relevant industry experience, motivation, work ethics, etc. You will notice that even this base index will not be a constant over time (in general, you learn as your career moves forward, but you may also pick up vices), nor will it be the same for all positions for which you are a potential candidate (industry experience and motivation may vary widely from one position to another).
If you want to consider that your TrueWorth is the amount of value you add to your company by direct result of your labor, you have to consider that this is proportional not only on your BaseWorthIndex, but on a number of force multipliers that your employer provides (or fail to provide). Doing the same excellent work for an obscure IT department in some random enterprise, for a high tech big corporation, for a SV startup or for a non profit results in very different outputs, and that more often than not these are out of your control.
In a sense, the employers with bigger multiplier factors want to bring in the best talent, and should pay above average salaries, industry-wise, but it's not required that this extra factor has to be directly proportional to the value added by your position.
If on the other hand, you want to define your TrueWorth in terms of a ratio between your BaseWorthIndex vs average BaseWorthIndex for your industry, you are in similar problems. Being (noticeably) above average means you may command above average salaries, but it does not mean an arithmetic proportion will be calculated; after all, our BaseWorthIndex is a fiction and it would be extremely hard to measure.
Then there is the issue of cost of living. Since as we discussed before, your compensation is not defined in absolute terms but relative to your peers, the issue of how much does it take to make a decent living at your current location comes to play. Take into account also that this is an asymmetric market and that you are always at disadvantage. I have seen more than one good friend and colleague been lured to NYC or SV/SF on the promise of plump returns, only to find out that cost of living lets them in worse conditions that what they had already achieved locally.