You either have something documented and quantified and measured and objective criteria tickboxes and deal with this style of failure mode, or you rely on subjective judgment and assessment and accept the failure mode of bias, nepotism, old boy's clubs etc. Of course the ideal case is to rely on the unbureaucratic informal wise and impartial judgment of some hypothetical perfect humans you can fully trust and rely on, and they always decide fully on merits etc. without having to follow any rigid criteria and checkboxes and numbers on hiring and promotion etc. But people are not perfect and society largely decided to go the bureaucratic way to ensure equal opportunities and to reduce bias through this kind of transparency.