Doctoral dissertations enable the transfer of research skills and capacities to future generations and the consolidation of lines of research in a given area of knowledge. The field of Library and Information Science in public universities in Spain is characterized by the supervision of doctoral theses by academics in the area. We identified active professors during the 2019-2020 academic year, their date of appointment as civil servants within the public university system, the dissertations that they supervised, and their participation in papers published in scientific journals. The analysis included 644 theses. About a quarter (23%) of university faculty have never supervised a doctoral thesis, and most faculty members and tenured professors (60%) show a lower than average rate of adviserships per year since their academic appointment. There is a high concentration of PhD advisers in just a few institutions and academics (8% of university professors have supervised 42% of the dissertations), with an important gender imbalance: women supervised an average of 1.8 dissertations, compared with 2.6 for men. Information units and services, study metrics and scientific publications, and information sources are the topics of 47% of the dissertations. Many of the professors with 10 or more adviserships (n/N = 12/18) lack a subject area specialization, and their role in PhD supervision was not related to their participation in research activities oriented toward publishing in scientific journals. Our results suggest that considering supervision of doctoral theses as an important academic merit could contribute to a further concentration of power and social capital among a small group of advisers. This phenomenon could reduce the plurality of topics addressed and favor suboptimal adviserships. The imbalances described emerge as another threat, exacerbating the epistemological crisis in the discipline and in the university studies in this area of knowledge.