What do we measure when we measure pubertal development? Problems and solutions in the conceptual basis of pubertal measures

Pubertal development influences adolescent health and behavior, but measuring puberty is challenging. Difficulties stem not only from practical issues, which have been the extensively discussed in the literature, but also from the very complexity of the theoretical basis of pubertal development from a physiological point of view. Here we discuss conceptual issues related to measuring and interpreting pubertal effects by first analyzing a widely used measure – age at menarche – as a case study. We use age at menarche as a starting point not because it is an ideal measure, but precisely because it is not, being well known for its limitations. However, our analysis shows that the most significant limitations this measure also apply to all currently used pubertal measures and arise from the fundamentally multifactorial physiological nature of pubertal development. Puberty is not a unitary phenomenon, cannot be measured directly nor be defined by individual makers, and its different markers are often discordant. We argue that a possible compromise between practical issues (building feasible/reliable measures) and theoretical ones (building conceptually sound and interpretable measures) is to treat puberty as the variance shared among multiple pubertal measures using suitable statistical methods.