The problem is that the ranking system is corrupted by favoritism and office politics. Every has already discussed the issues around brown-nosers and so-called "high potentials" having protected status, but when rankings are distributed across a whole department, a lot can depend on which group you're in. For example, the 10-strong R&D group responsible for Mobil 1 all benefit from the halo effect of the product with which they're associated, even though there are really only 3 or 4 people who are actual formulators and 1 of these is the true lead person who directs the others.
The other people in the group are just involved with organizing specific blend studies and rig/engine tests for API specification and OEM requirements, or even just loading formulation details and other information into the product specification database (for the blend plants and marketing advisors). While their work is necessary and important, the staff working under direction or simply doing clerical work will all be ranked significantly higher than formulators with similar age and years of service who are independently formulating other lubricants (e.g. diesel engine, marine or especially industrial) .... just because they are associated with Mobil 1 and they must be the best because of this.
There is no way you can tell me that is fair or right.