Should Archaeologists Care about 14C Intercomparisons? Why? A Summary Report on SIRI

Abstract Radiocarbon ( 14 C) dating is used widely in many projects as a basis for the creation and testing of chronological constructs. 14 C measurements are by their nature complex and the degree of sample pretreatment varies considerably depending on the material. Within the United Kingdom and Europe, there are a number of well-established laboratories and increasingly, archaeologists are not just commissioning new dates, but also using statistical modelling of assemblages of dates, perhaps measured in different laboratories, to provide formal date estimates for their sites. The issue of comparability of measurements (and thus bias, accuracy and precision of measurement) from the diverse laboratories is one which has been the focus of some attention both within the 14 C community and the wider user communities for some time. As a result of this but also as part of laboratory benchmarking and quality assurance, the 14 C community has undertaken a wide-scale, far-reaching, and evolving program of intercomparisons, to the benefit of laboratories and users alike. This paper summarizes the most recent exercise, the Sixth International Radiocarbon Intercomparison (SIRI).