15 - Quantification

Summary

Introduction

This subject has generated more heat than light for many years. Although it has been generally (but not universally) appreciated as a ‘good thing’, its aims and in particular its methods have been a source of controversy. To try to resolve this problem we must go back to basics. At its simplest, quantification is an attempt to answer the question ‘how much pottery is there?’ – in a context, feature, site or other grouping. An answer to this question as posed would be of little use, for two reasons. First, we do not know how much of the archaeological record we possess: do we, for instance, have all of a ‘site’ (and does the term ‘site’ really mean anything?), or was rubbish dumped beyond the confines of what we regard as the site? Or was it dumped on a midden and used to manure the fields? Second, even if we had a complete record (and could tell that we had) we would still not be able to relate our ‘death’ assemblage to a ‘life’ assemblage of pots actually in use, since the relative quantities depend on the average lifespans of the pots. An assemblage of ten pots, for example, might have been used simultaneously with a life of (say) five years each, or successively with a life of only six months each. Such differences are, at present, unresolvable.

The second step is to say that the main interest lies, not in the overall size of each assemblage (though that may be important when it comes to questions of reliability of evidence), but in their compositions, that is the proportions of the various types that make them up. This overcomes most of the first problem (although we should note that large assemblages are statistically more likely to include examples of rare types than are small ones, simply by virtue of their size [Cowgill 1970]), but makes no impression on the second. For example, suppose our hypothetical assemblage of ten pots consists of nine drinking vessels and one storage jar. It may be that the average life of the former is, say, six months, while that of the latter is five years.