This is mainly a statistical matter and probably an often misuse of
statistics.  A mean is meant to give an idea about a data set not really
predict anything- can be if the data are normally distributed.  If you have
a group of data with breaks in it then the mean nay well fall in one of
those breaks or be pulled left or right due to outliers.  Shouldn't you just
use your latest dated artifact within a certain context anyhow?  Maybe using
the mode may be more informative.


>From: david G Orr <[log in to unmask]>
>Reply-To: HISTORICAL ARCHAEOLOGY <[log in to unmask]>
>To: [log in to unmask]
>Subject: Re: TPQs etc
>Date: Tue, 26 Aug 2003 06:32:22 +0000
>
>I must say I have used TPQ dating throughout my career and
>listened to numerous mean ceramic date papers. I guess there
>is utility somewhere but I agree with Pratzelis et al on this
>one. Working in POMPEII for forty years sharpens your acuity
>to TPQ!!! I remember the Italians in 1991 excavated a small
>house in Region One of Pompeii that was CRAMMED with
>exquisitely engraved Greek bronzes from the late fourth and
>early third centuries B.C.E. Wow, would the mean date tell a
>crazy story there when you averaged them in with the later
>Roman bronzes (which were far fewer). Yet all the bronzes
>were sitting on the floor covered by Vesuvius.In Pompeii, the
>TPG appears miraculously after you excavate the last of those
>little ash bits (lapilli) and its August, 79 C.E.  At City
>Point we excavated a cellar filled with thousands of objects
>and dated it to the early 1760's because of the absence of
>creamware except for this wondrous proto creamware that
>resembled scratch blue stoneware in decoration. The bottle
>glass shapes also confirmed our interpretation. And since the
>main house was built in 1763 our inference was House One went
>down(probably not house One by the way) and House Two went
>up. Sure, a Victorian stamped weight wandered into the fill
>by way of some convenient biofactual portal but thats
>explainable. Anyway, the Europeans pretty much use TPQ
>ubiquitously.I just particpated in the excavation of a HUGE
>Roman villa at Cumae and there was lots of earlier ceramics
>but the newest objects (glass mostly) confirmed the building
>date. Constantinian coinage showed the site was exposed in
>the fourth century C.E. Interesting discussion.

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