This chapter introduces a cutting-edge study on the composition of the bodies under analysis to assess how this may influence their adjudication. An empirical quantitative study on the judges’ and commissioners’ background is combined with an analysis of their ‘judicial behaviour’ through their separate opinions. This demonstrates that judicial convergence could be partly due to the personal identity and background of those individuals called to interpret the law and adjudicate the cases. In particular, this chapter shows signs of a possible ‘Europeanisation’ of the African and Inter-American judges, which could encourage the African and Inter-American Court to converge with the European case-law. The chapter also discusses the role played by the secretariats in influencing the adjudication of human rights regional and international bodies. Drawing on interviews with members of the registries of the three regional courts, it concluded that specific agendas, priorities and internal organisations may encourage judicial convergence.