While I support pay transparency on principle, I have never seen it work. In practise, no two employees are ever equal. Even those with the same years of experience, the same qualifications, and the same roles. One might be happy to work late. The other might be happy to pick up the phone on weekends. One might prefer working alone. The other might play better with colleagues. One might offer to take on more projects. The other might not, but they have better attention to detail. The differences go on ad infinitum. There is no "objective" way to determine the market value of each of these two employees. The best we can do is let each business make subjective judgments of each employee. We know this is far from perfect, but it could be more fair than paying two very different people the same wages just because they studied the same thing at university and worked in the industry for the same length of time. One of them will be contributing more to the business bottom line - sometimes significantly so - and they probably know it. They'll leave if they're paid the same as their lesser-performing colleague.