This editorial introduces a special issue of Large-Scale Assessments in Education (LSAE) that addresses key challenges in analyzing longitudinal data from large-scale studies. These challenges include ensuring fair measurement across time, developing common metrics, and correcting for measurement errors. The special issue highlights recent methodological innovations, particularly for studies like the National Education Panel Study (NEPS), providing approaches for improving the accuracy and robustness of longitudinal educational research. The papers in this issue present advances in methods for estimating trends, incorporating background information, and analyzing longitudinal relationships between constructs. Innovative approaches such as Bayesian modeling for borrowing historical information, continuous-time models for capturing developmental trends, and plausible value estimation provide practical solutions for researchers working with complex longitudinal data. In addition, the issue presents new software tools that facilitate the implementation of these advanced methodologies. Together, these papers contribute to both the theory and practice of educational assessment and provide valuable insights for those working with longitudinal data in national and international panel studies.