In forensic science, anthropology, and archaeology, several techniques have been developed to estimate chronological age in both children and adults, using the relationship between age and morphological changes in the structure of teeth. Before implementing a statistical model to describe age as a function of the measured morphological variables, the reliability of the measurements of these variables must be evaluated using suitable statistical methods. This paper introduces some commonly used statistical methods for assessing the reliability of procedures for age estimation in the forensic field. The use of the concordance correlation coefficient and the intraclass correlation coefficient are explained. Finally, some pitfalls in the choice of the statistical methods to assess reliability of the measurements in age estimation are discussed.