The use of computational methods to assign absolute datings to language divergence is receiving
renewed interest, as modern approaches based on Bayesian statistics offer alternatives to the discredited techniques of glottochronology. The datings provided by these new analyses depend crucially on
the use of calibration, but the methodological issues surrounding calibration have received comparatively little attention. Especially, underappreciated is the extent to which traditional historical linguistic
scholarship can contribute to the calibration process via loanword analysis. Aiming at a wide audience, we provide a detailed discussion of calibration theory and practice, evaluate previously used
calibrations, recommend best practices for justifying calibrations, and provide a concrete example of
these practices via a detailed derivation of calibrations for the Uralic language family. This article aims
to inspire a higher quality of scholarship surrounding all statistical approaches to language dating,
and especially closer engagement between practitioners of statistical methods and traditional historical linguists, with the former thinking more carefully about the arguments underlying their calibrations
and the latter more clearly identifying results of their work which are relevant to calibration, or even
suggesting calibrations directly.