BCal is an online calibration
system that uses Bayesian statistics. It is much more complex to
use, but then the underlying theory is more complex. The significant
difference between this method and Calib is that extra
information is included, such as the relative locations of the
ages in a sequence. If one is above the other, it has to be
younger, and this will be reflected in the calibration returned.
This is easy to test: provide two dates that are far apart in age,
calibrate, and examine the result. Then move one of them so that
its error range overlaps the other, and calibrate again. Compare the
calibration of the unmoved date: it should have changed.
This is potentially a very powerful system, but there are
obvious pitfalls that need to be avoided: there is no longer
an exact one-to-one relationship between radiocarbon age and its
calibration, for example.
The BCal system creates accounts for users and stores their
data on the server (located in Cardiff, UK). Setting up a calibration
is a little complex at first, but worth the trouble, and the
work is saved for future use automatically.