Relative chronometric dating techniques
Archaeologists use many different techniques to determine the age of a particular artifact, site, or part of a site.
Douglass believed that solar flares affected climate, and hence the amount of growth a tree might gain in a given year.
Absolute dating, the ability to attach a specific chronological date to an object or collection of objects, was a breakthrough for archaeologists.
Until the 20th century, with its multiple developments, only relative dates could be determined with any confidence.
Seriation is thought to be the first application of statistics in archaeology. The most famous seriation study was probably Deetz and Dethlefsen's study Death's Head, Cherub, Urn and Willow, on changing styles on gravestones in New England cemeteries.
The method is still a standard for cemetery studies.