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Standardizing ordinal subadult age indicators: Testing for observer agreement and consistency across modalities

NCJ Number
Forensic Science International Volume: 320 Dated: 2021
Date Published

This study evaluated observer agreement of epiphyseal fusion and dental development stages obtained on CT scans of a U.S. sample and the consistency of epiphyseal fusion stages between CT scans and projected scan radiographs/scout images (U.S. CT sample), as well as between dry bones and conventional x-rays (Colombian osteological sample).


Skeletal and dental data for subadult analyses obtained from dry bones or various types of medical images, such as computed tomography (CT) scans or conventional radiographs/x-rays, should be consistent and repeatable to ensure method applicability across modalities and support combining study samples. The results of the current study indicate that both intra- and interobserver agreements of scores on CT scans were high (intra: mean Cohen’s kappa = 0.757–0.939, inter: mean Cohen’s kappa = 0.773–0.836). Agreements were lower for dental data (intra: mean Cohen’s kappa = 0.757, inter: mean Cohen’s kappa = 0.773–0.0.820) compared to epiphyseal fusion data (intra: mean Cohen’s kappa = 0.939, inter: mean Cohen’s kappa = 0.807–0.836). Consistency of epiphyseal fusion stages was higher between dry bones and conventional x-rays than between CT scans and scout images (mean Cohen’s kappa = 0.708–0.824 and 0.726–0.738, respectively). Differences rarely surpassed a one-stage value between observers or modalities. The complexity of some ossification patterns and superimposition had a greater negative impact on agreement and consistency rates than observer experience. Results suggest ordinal subadult skeletal data can be collected and combined across modalities. (publisher abstract modified)


Date Published: January 1, 2021