The real issue is not with jobs where the tasks are directly comparable and everything is observable.

The real issues are with power plays where people take advantage of individuals to create power imbalances.   This is very hard to detect by doing a simple numerical analysis.   Even "big data" approaches can't detect this kind of manipulation easily.

I know I've done work where the going rate is at least double my pay, and a lot more as an independent consultant.   Interestingly, attempts to deal with the situation are all "flattened" or manipulated.   

For example, when a job opportunity seems to be going somewhere, suddenly, the communications will cease with no explanation.   This will happen in a way that suggests someone has been (illegally) communicating with the hiring manager in a defamatory way about me.   This hasn't happened only once.   It is a pattern.

This is criminal harassment and women are overwhelmingly the victims in situations involving criminal harassment.