This publication describes how components of an administrative data system on justice for children function in systems that have varying levels of maturity. The aim is to facilitate the identification of general areas that would benefit from targeted intervention and investment. This said, since countries develop their administrative data systems differently, there is no one-size-fits-all approach to strengthening these systems. Each country will have different requirements to improve its system. It is also important to note that there are no specific stages through which an administrative data system must develop, since emerging technology could, for instance, ‘leapfrog’ a low-income country from a paper-based system to a state-of-the-art electronic database.