The UNAM counts with a kind of "ranks" which exists separately for lecturers (profesor), researchers (investigador) and technicians (técnico académico), or as a combined function (investigador/profesor).
The lowest rank is Asociado A, the highest Titular C. Income, the right to participate in commissions and councils, and the right to submit internal, UNAM funded, projects etc. depends greatly on the level. Requirements to rise within the hierarchy vary from institute to institute, and are becoming more and more difficult (because it includes an increase in salary). A person who became Titular C let's say ... 15 years ago would now probably not even qualify to become a Titular B. Therefore the rank is not a good measure for scientific quality and reputation within the community. If people once reached a certain level, they are never lowered even if they fall into a state of suspend animation.