In archaeology, debitage is all the material produced during the process of lithic reduction – the production of stone tools and weapons by knapping stone. This assemblage may include the different kinds of lithic flakes and lithic blades, but most often refers to the shatter and production debris, and production rejects.
Debitage analysis, a sub-field of lithic analysis, considers the entire lithic waste assemblage. The analysis is undertaken by investigating differing patterns of debris morphology, size, and shape, among other things. This allows researchers to make more accurate assumptions regarding the purpose of the lithic reduction. Quarrying activities, core reduction, biface creation, tool manufacture, and retooling are believed to leave significantly different debitage assemblages. Lithic manufacture from a quarried source, or from found cobbles also leave different signatures. Some claim that they can determine the sort of tools used to create the debitage. Others feel it is possible to effectively estimate the work-hours represented, or the skill of the workers based on the nature of the debitage.
Debitage analysis of biface reduction can be used to determine what stage of reduction is represented in waste. Stahle and Dunn (1982) found that, as waste flake size decreases from initial to final stages in biface production, systematic changes in flake size can be used to identify stages of reduction in anonymous debitage samples through comparison with experimental assemblages. Use of Weibull distributions and least square analysis helped Stahle and Dunn confirm that this method can be used backward to estimate reduction stages of particular debitage frequencies. Other studies comparing the debitage of bifacial reduction during different stages has not yielded such positive results. Patterson (1990) was unable to distinguish between the stages of initial edging and secondary thinning using statistical analysis of 14 experimental assemblages.