The acetabulum as an adult age marker and the new IDADE2 (the IDADE2 web page).

OBJECTIVE In 2006, an age estimation method was proposed utilizing Bayesian inference to interpret age-progressive changes in the acetabulum. This was accompanied by the IDADE2 software to facilitate calculations. However, the MS-DOS operating system on which the software was based became obsolete. The main goal of this article is to present the new IDADE2, which incorporates web-based facilities. MATERIALS AND METHODS The original IDADE2 has been re-written in R and presented as a web page. As in the original, this web page uses Bayesian inference to estimate age of unidentified individuals. The materials used to create the reference datasets of this web page include acetabular scores from documented skeletal samples from Spain (n = 24♀ and 52♂), Portugal (n = 317♀ and 294♂), and the US (n = 370♀ and 456♂). RESULTS The IDADE2 website has eight sections. Six of these are informative to guide the user. The other two (Option 1 and Option 2) are dedicated to estimating age at death. Option 1 allows users to estimate the age of individual(s) in their test sample based on our reference data of acetabular scores. Option 2 allows users to estimate age from the acetabulum with their own reference and test collections or-if the users prefer-another age marker and method of choice. DISCUSSION The IDADE2 website is applicable both to forensic anthropological casework on single individuals and to bioarchaeological analyses of large skeletal samples. This website is easy to use and freely accessible, responding to previous critiques and incorporating method advancements.