This last of four volumes on Statistical Science: From Theory to Applied Research presents peer-reviewed short papers on theoretical and applied statistics presented at the Joint Meeting SIS-FENStatS 2026, held in Rome, Italy, on June 22–25, 2026. The meeting brought together the 53rd Scientific Meeting of the Italian Statistical Society (SIS 2026) and the 1st Scientific Meeting of the European Statistical Societies (FENStatS 2026) promoted by the Federation of European National Statistical Societies. This volume features the last part of the contributions presented in the Contributed Sessions.

The contributions present modern methodological developments and innovative applications in a wide variety of fields and address current challenges in statistical science. The topics covered include, but are not limited to, high-dimensional and multivariate statistics, functional data analysis and complex data structures, Bayesian statistics, time series analysis, dependence and extreme values, statistical learning, machine learning and AI, network science, analysis of directional and compositional data, spatial, spatio-temporal and environmental statistics, biostatistics and the analysis of medical data, social statistics, demography,  economic statistics, as well as survey statistics, official statistics and public policy. Given this variety, the book also demonstrates the importance of statistical science and the responsible use of quantitative methods in addressing societal and environmental challenges related to sustainable development.

The Joint Meeting SIS-FENStatS 2026 was the first event of its kind ever organized at the European level. It provided an important forum for dialogue, exchange and collaboration among national and international contributors from academia, national and international institutions, and industry, working across statistics, demography, and applied statistical fields.

Francesca Martella is an Associate Professor at the Department of Statistical Sciences, Sapienza University of Rome, Italy.

Serena Arima is an Associate Professor at the Department of Human and Social Sciences, University of Salento, Lecce, Italy.

Maria Francesca Marino is an Associate Professor at the Department of Statistics, Computer Science, Applications "G. Parenti", University of Florence, Italy.

Cristina Mollica is an Associate Professor at the Department of Statistical Sciences, Sapienza University of Rome, Italy.