My academic years presented a clear formula for measuring merit: everyone got the same assignments or tests and the final grade depended on one's efforts and talents in preparing for these.
I started my professional career in a global investment bank in New York City. It was a very competitive and somewhat political environment, yet it was fairly meritocratic. Only the merit criteria changed drastically from my college years so I had to figure out the written and unwritten
One of my over-achiever students, "Belinda" worked in a commercial real estate company and even those it was her first year in this role, she had exceeded her annual sales goals already in early October.
Her HR representative was really impressed with her and told her that it will be completely reasonable to discuss a raise with her supervisor. Belinda also found out from another colleague that she was about to get an important large client account added to her portfolio.