Monday, July 4, 2011

Boom-time machine

I lifted the title for this post from the Economist article of the same name:

Radiocarbon dating provides a range, often spanning 200 years or more, rather than an exact date for a site. Stratigraphy, which looks at the soil layers in which artefacts are found, tells you only which ones are older and which younger. None of these data is precise. They do, however, limit the possible range of dates. And by using a statistical technique called Bayesian analysis it is possible to combine such disparate pieces of information to produce a consolidated estimate that is more accurate than any of its components. That results in a range that spans decades, not centuries.
A team led by Alex Bayliss, from English Heritage, a British government agency, has just used this technique to examine digs from hundreds of sites around Britain. The results have caused them to reinterpret the Neolithic past quite radically.
English Heritage now plans to apply the technique to another murky era of British history, the early Anglo-Saxon period between 400AD and 700AD.

Essentially, archaeology has just caught up with other disciplines, like biology, and started using more sophisticated statistical techniques. Bayesian inference is...well, hmmn, I think of it as constant-improvement statistics: you look at the result/event, and fold it into the prior probability/expectation of that result/event, and end up with an improved understanding of what the result means. Sort of like a statistical feedback loop--but, er, not. Oh, just go to Wikipedia and read for yourself.

The point, for me, is that they are going to take a look at Hild's era. More accurate info about change in the Heroic Age excites me to popping point. I want them to do it now. Now now now!

My big worry? That Hild will be published and then I'll find out, in light of the new interpretations of data, that everything we thought we knew is wrong. That will drive me crazy. If I honestly thought Alex Bayliss and his team could get the work done by the end of the year, I'd delay turning the book in. But, like everything related to archaeology, the process is slow.

It's worth reading the whole article, despite sentences such as "None of these data is precise." An example of technically correct grammar turning one's head inside out like a sock.

Here's Kelley's latest Clarion West write-a-thon piece, "The Last Cafe."

The sign said The Last Cafe, but the place looked like what Annie thought of as a regular house, small and wooden with a covered front porch, sleepy in the shade of a stand of oaks dripping Spanish moss. Blue jays scracked overhead. It was going to be a hot day. Annie smelled salt in the air.

She left Bridget in the small parking lot while she went around back. She had learned that taking a little one to the door only made it more likely folks would say no. “Stay right here and wait for me,” she said. Bridget nodded tiredly and clutched her beanbag frog. [more]

You should read the whole thing. It will make you cry (or clench your jaw and blink sternly, depending). So if it did make you blink, even just a little, sponsor Kelley. All money will benefit all the children clutching frogs students of Clarion West next year. You can read all Kelley's other pieces here for free (though you'll feel better, I'm sure, if you've added a little something to the cause).

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