The evaluation system is an important component of the institutional arrangements that may shape the career trajectories of researchers. Using logistic regression and recursive partition models, we analyze the resulting key individual level factors that seem to play an important role in the promotion of researchers through the research evaluation system of the Argentine National Council of Scientific and Technical Research (CONICET) in two selected fields, namely, the basic and applied sides of the molecular biology and biotechnology fields. The data are from 599 researchers who are members of the scientific and technological "research career" of the Council. We analyze the promotion through the first two stages of the process, namely, promotion from "assistant investigator" to "adjunct investigator" and from the latter to "independent investigator" for the entire cohort of candidates eligible during years 2013 and 2014. We find that time in grade (a strong normative requirement of the system), a moderate number of publications of international quality, evidence of mentoring the future generation of researchers, and registered technological production are the main factors that predict researchers' promotion. Conversely, the specific academic profile, early external funding, gender, time from graduation, and postdocs abroad do not have a significant effect.