8/8/2019 A Method for Measuring Relative Abundance of Fragmented Archaeological Ceramics - John E. Byrd and Dalford D. … http://slidepdf.com/reader/full/a-method-for-measuring-relative-abundance-of-fragmented-archaeological-ceramics 1/7 A Method for Measuring Relative Abundance of Fragmented Archaeological Ceramics Author(s): John E. Byrd and Dalford D. Owens, Jr. Source: Journal of Field Archaeology, Vol. 24, No. 3 (Autumn, 1997), pp. 315-320 Published by: Boston University Stable URL: http://www.jstor.org/stable/530687 Accessed: 13/02/2010 10:21 Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/action/showPublisher?publisherCode=boston . Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission. JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Boston University is collaborating with JSTOR to digitize, preserve and extend access to Journal of Field Archaeology.
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8/8/2019 A Method for Measuring Relative Abundance of Fragmented Archaeological Ceramics - John E. Byrd and Dalford D. …
A Method for Measuring Relative Abundance of Fragmented Archaeological Ceramics
Author(s): John E. Byrd and Dalford D. Owens, Jr.Source: Journal of Field Archaeology, Vol. 24, No. 3 (Autumn, 1997), pp. 315-320Published by: Boston UniversityStable URL: http://www.jstor.org/stable/530687
Accessed: 13/02/2010 10:21
Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at
http://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unless
you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you
may use content in the JSTOR archive only for your personal, non-commercial use.
Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained athttp://www.jstor.org/action/showPublisher?publisherCode=boston.
Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed
page of such transmission.
JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of
content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms
of scholarship. For more information about JSTOR, please contact [email protected].
Boston University is collaborating with JSTOR to digitize, preserve and extend access to Journal of Field
Dalford D. Owens Jr.University of Tennessee, Knoxville
Knoxville, Tennessee
Archaeologistsommonly se imple ounts f specimenss a measure f relative bun-danceforvariousfra,gmentedrchaeological aterials. imple ounts, owever,reprone o errordue to thedifferential ize offragments.A more alid measure hat ap-proncimatesurfacearea is theeffective rea (EA). Thismeasure ffers simple olutionto theproblem f quantifying eramicsfrom rchaeologicalontexts.
Introduction
Archaeologists have long been using simple sherd
counts as a measureof the relativeabundanceof ceramic
types (cf. Kidder 1931; Ford 1952). The simple sherd
count is derived by counting the fragmentsof broken
ceramic vessels. Researchersusing simple counts often
encountererrorsdue to varying herd size (Orton, Tyers,and Vince 1993; Childress 1992; Ford 1952; Gifford
1951, cited in Baumhoffand Heizer 1959), particularly
when sherds of one type are highly fragmentedwhile
others are not. In most cases it is assumedthat varying
sherdsizes will have a minimaleffect on the analysis e.g.,
Ford 1952; Childress 1992). Some archaeologists e.g.,
Orton, Tyers, and Vince 1993: 21; Chase 1985: 213;
McNutt 1973: 45; Solheim 1960: 325; Gifford 1951:
223, cited in Baumhoff and Heizer 1959: 309) have
expressedconcern with this assumptionand have ques-
tioned the use of sherdcounts as a measure f the quantity
of pottery (Orton, Tyers, and Vince 1993: 21; Chase1985: 213).
A central heme of this paper s that sherdcounts havea
low degree of validity (Nance 1987) as a measure of
relativeabundance.A measure'svalidity s determinedby
how well it measures what it is intended to measure(Nance 1987: 280); thus, it is necessary o state that the
assumptionhere is that measures of the relative abun-
dancesof specificclassesof ceramicmaterials re generally
intended to measure he quantityof ceramicmaterialbe-
longing to each class (not necessarilyhe numberof items
such as pots or bowls).
Orton, Tyers, and Vince (1993: 23) have identifie
three important ypes of evidencecommonlyprovidedby
ceramicanalyses n archaeology: atingevidence,distribu
tional evidence,and evidence or function and/or status
The full developmentof these areasof research nvolvethe use of measuresof relativeabundance. n sites where
ceramics replentiful, hey are often the primarymeansof
dating the context in which they are found as well as the
materials ecovered n association.Date rangesareassigned
based on the proportionsof types with known tempora
distributions.Distributions f ceramic ypescan shed light
on specificaspectsof past lifeways uch as tradepractice
(Orton, Tyers,andVince 1993: 23). An effectivemeansof
analyzing ype distributiondata s to present he data n a
quantitative istributionmapwhereproportions f respec
tive types at various ites are displayed Orton, Tyers,and
Vince 1993: 201). Information elating o the functionofindividualpots can naturally ead to an interpretation f
site function when proportions of different functiona
types present in an assemblageare ascertained Orton
Tyers,andVince 1993: 29).
Gifford (1951) was one of the earliestresearchers o
attempt to improve upon the simple sherd count as a
measureof relative bundance.He employed herdweigh
and found that "weighing sherds seems to give more
accuratestatistical esults than counting them" (Gifford
A M e th o d f o r Measuring R e l a X d v e
Abundance o f Fragmented
Archaeological C e r a m i c s
8/8/2019 A Method for Measuring Relative Abundance of Fragmented Archaeological Ceramics - John E. Byrd and Dalford D. …
calculated,as indicatedby the large standarddeviations(Childress1992: 39).
EAvaluesof sherds,alongwithestimates f wholevesselsurfacearea,makepossiblea simpler,more accurateap-proachto the problemof convertingsherds o a measure
that can be combinedwith whole vesselquantities.Thisapproach estson the factthat EAcan be predicted romsurfacearea.Ceramicvessels of ten differentshapesandsizes were assembledto investigate he relationshipbe-tween EA andsurfacearea.Surfacearea orallvesselswasestimated(in squareinches) and the vesselswere sub-sequentlybroken o varyingdegreesand the EAmeasured.Surfacearea and EA for the threevessels n the previousexperimentwereincluded.
A simple inearregression nalysiswasdonewithsurfacearea as the independentvariableand EA as the responsevariable.Because thereare severalvaluesof EA for eachvalue of surface area,it is necessary o formally est forlinearity see Zar 1984: 282). The one-tailedF-test forlinearitydescribed n Zar(1984: 282) wasused to test thenull hypothesis hat the dataarelinearlydistributed.Thenull hypothesiswas accepted(F = -3.92, p > 0.25). Theregressionanalysis esulted n a correlation oefficientof0.996 (R2= 0.991) andanoverall ignificanceevelof p =0.000 (F = 4666.279). It is clearthat total EA for anarchaeological ssemblage an be effectively stimatedbyemployinga regressionmodel to convertvessel surfaceareas o EA.The modelpresentedhere FIG. 1),
EA = 0.831 (surf6lceIre6l)is generallyapplicable o most ceramicvessels, but moreprecisemodels can be calculatedby using dataobtainedfromvessels of the specificshapesof interest.
Discussion
Analyticalproceduresn archaeologyhave traditionallyinvolvedusingsimplesherdcountsforrespectiveypesasameasureof relativeabundance.Whensuch a proceduresappliedto the experimental ypes above, it resultsin adistorted picture of the ceramicassemblagewhere therelativeabundancesarered 74.5%,black
22%,andwhite3.5%.These percentages uggest that thereareconsider-able disparitiesn the quantitiesof ceramic n each type.Percentagesbased on EA producea drastically ifferentpicturewith the red composing30%of the assemblage,while blackandwhite constitute35% ach.It is clear hatEA provides a more accuratemeasureof relativeabun-dance.
The archaeologicalpplicationncludeda statisticalestthat showed that relativeabundancesbasedon EA weresignificantly ifferent romthose basedon simplecounts.
250
200
150
:LL
100
50
o0 100 200 300
SA
Figure 1. Regressionmodelwith EApredictedrom surfacearea hatwascalculated iom anexperimentalssemblagewithvesselsof vary-ing sizesandshapes.
This findingverifiesthe impressionof the authorsthatsherdsarenot consistently he samesize but vary,some-iimes considerably.The frequencyseriaiionusing sherdcounts showsthatvaryingsherdsizescan indeedlead to
errorsin interpretaiion hat are archaeologicallyignificant.
Acknowledgments
The authorswould like to thankthe editor,RicardoJ.Elia,andthe anonymous eviewers ortheirmanyvaluablcomments on this paper.R. P. Stephen DaxTis, r. andRobertC. Dunnellarealsoacknowledged orcommentingon earlier ersionsof thiswork.The contributions f all oftheabovehavegreatlymprovedhispaperbutresponsibiityfor anyshortcomings estssolely uponthe authors.
John E. Byrd(Ph.D. University f Tennessee,Cnonsville,1994) is a Reseolrchssociolten theInstitute or Histori-cal olndCulturollReseolrchlndVisitingAssistolnt rofes-sor in theDepolrtmentfAnthropologyltEolstColrolinoUniversity.Molilingolddress:epolrtmentfAnthropol-osgy, olstColrolinol niversity,Greenville,NC 27858.
DollfordD. Owens r.is a grolduoltetudent n olnthro-pology lt the University f Tennessee,Cnonsville.olilingolddress:epolrtmentfAnthropology, niversity f Ten-nessee,Cnoxville,Cnonsville,N 37990-0220.
8/8/2019 A Method for Measuring Relative Abundance of Fragmented Archaeological Ceramics - John E. Byrd and Dalford D. …