Best practices for calibrating and reporting stable isotope measurements in archaeology

The use of isotopic measurements in archaeological research has increased rapidly over the past ~ 25 years, owing largely to the proliferation of the instruments required to produce these measurements relatively quickly and cheaply. Unfortunately, the understanding of how to adequately calibrate and report these isotopic data has not kept pace. We surveyed nearly 500 archaeological research papers published within the past 25 years that presented original isotopic data. We found that, generally, the majority of studies do not provide adequate information regarding how isotopic measurements were calibrated, nor how analytical uncertainty (precision and accuracy) was assessed. We review and present recommendations for data analysis, calibration, and reporting to aid archaeological researchers who use isotopic measurements and practices. We present a simple method for quantifying standard analytical uncertainty using data that would be provided by most laboratories.