I saw an article about Google about six months ago that said that people in the same position could be paid wildly different amounts based on the company's asse

I saw an article about Google about six months ago that said that people in the same position could be paid wildly different amounts based on the company's assessment of their contribution and the cost to replace them. The first thing I thought was that this is a good way to compensate people. Second thought was that it would cause much gnashing of teeth to anyone who decides to look at equal pay for equal work based on job title and seniority. Does anyone have that article?