to summarise, ur boss is going to promote someone based on their performance. n their performance is usually based on the boss' subjective observation of "work", which may or may not include any actual work done to their fellow colleagues but more of befriends with the boss (i believe this behaviour is stimes refered to as "favourism"). well since we'r all humans, it's hard to critise ur boss for being bais - it's just human nature to promote his/her most favourite subordinate who excels in areas such as going to facial or shopping or lunch or the toilet together or kissing undesirable body parts such as the @ss, instead of producing actual work in many others' eyes!
so to make the world fair and happy, and riding on the basis that "all human are equal", i propose to all the bosses n HR mgrs to exercise their limited knowledge on statistics - think of the random selection concept! this gives everyone a fair chance regardless of ur subjective bias to think whether or not a person is talented or productive or whatever!
to help you make it truly random, i've thought of the below 2 tools in addition to the above option with darts...
p.s. actually based on some true stories, i start to realise that *maybe* HR n business managers are already using these methods! n that's y some ppl got promoted instead of others without much reasons to it! hah!