One of the most frequent questions I get from entrepreneurs is "what is market?" with regard to compensation, particularly for executives such as the Chief Technology Officer or VP of Sales. It is such a frequent question that it was the topic of one of my first blog posts 7 years ago.
Talent is the most important ingredient at a young company, and so there is great energy put into trying to be thoughtful to pay a fair market rate for good talent, particularly in light of a very competitive market.
Fortunately, like most things in the land of startups, the world has gotten much more transparent in the last few years and there's a plethora of good data available to help answer this question.
One of the best is my Harvard Business School colleague Noam Wasserman's annual compensation study that he performs in partnership with J. Robert Scott and E&Y. Noam describes the study a bit in his blog post, but if you want a far more detailed view of "what is market" than my amateur summary - sliced and diced by industry, size of company, amount of capita and more - then this study is for you. It's a give-get model - if you give your data, you get the aggregated data back in all it's gory detail.
I highly recommend it.