Log‐ratio Compositional Data Analysis in Archaeometry*

Baxter, Michael; Freestone, Ian C.

doi:10.1111/j.1475-4754.2006.00270.x

Cited by 99 publications

(71 citation statements)

References 18 publications

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“…Aitchison, 1986;Baxter and Freestone, 2006;Pawlowsky-Glahn and Egozcue, 2006). It has been widely recognised that compositional data provide relative rather than absolute information and, therefore, the use of ratios rather than pure elemental concentrations is highly recommended.…”

Section: Discussionmentioning

confidence: 98%

On the provenance and manufacture of red-slipped fine ware from ancient Cassope (NW Greece): evidence by X-ray analytical methods

Papachristodoulou

Gravani

Oikonomou

et al. 2010

Journal of Archaeological Science

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Section: Discussionmentioning

confidence: 98%

On the provenance and manufacture of red-slipped fine ware from ancient Cassope (NW Greece): evidence by X-ray analytical methods

Papachristodoulou

Gravani

Oikonomou

et al. 2010

Journal of Archaeological Science

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“…First, sediment volume is not technically independent of the frequencies of finds, since those finds contribute to the total volume; find-density data are still technically compositional -analogous, perhaps, to trace elements in ceramic or glass compositional analysis. This has troubling implications for multivariate analyses (see Aitchison et al 2002;Baxter and Freestone 2006), but becomes a problem for comparing find deposition rates only when the finds in question make up a substantial percentage of the sediment matrix. Bone find-density data are thus of limited value for comparing taxonomic frequencies in extremely bone-rich contexts such as fish middens or Roman urban 'soup kitchen' deposits.…”

Section: Monte Carlo Simulationmentioning

confidence: 99%

Catch Per Unit Research Effort: Sampling Intensity, Chronological Uncertainty, and the Onset of Marine Fish Consumption in Historic London

Orton

Morris²,

Pipe

2017

Open Quaternary

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As the cumulative volume of ecofactual data from archaeological sites mounts, the analytical tools required for its synthesis have not always kept pace. While recent attention has been devoted to spatial aspects of meta-analysis, the methodological challenges of chronological synthesis have been somewhat neglected. Nowhere is this issue more acute than for urban sites, where complex, well-dated stratigraphy; rich organic remains; and multiple small-to medium-scale excavations often lead to an abundance of small datasets with cross-cutting phasing and varied chronological resolution. Individually these may be of limited value, but together they can represent the environmental and socioeconomic history of a city. The challenge lies in developing tools for effective synthesis.This paper demonstrates a new approach to chronological meta-analysis of ecofactual data, based upon (a) use of simulation to deal with dating uncertainty, and (b) calibration of results for variable research intensity. We apply this approach to a large body of historic-period fish bone data from London, revealing otherwise undetectable detail regarding one of the most profound shifts in medieval English economic and environmental history: the sudden onset of marine fishing commonly known as the Fish Event Horizon. Most importantly, we show that this phenomenon predates any visible decline in deposition of freshwater fish, and hence cannot have been driven by depletion of inland fisheries as has sometimes been suggested.The R package developed for this research, archSeries, is freely available.Keywords: zooarchaeology; meta-analysis; medieval fishing; environmental history; chronological uncertainty; urban archaeology; fish bones; aoristic analysis; Fish Event Horizon; sampling intensity IntroductionRecent decades have seen widespread recovery and analysis of a wide suite of ecofactual remains from archaeological sites, particularly in territories with systematic frameworks and guidance for development-led archaeology. As the cumulative volume of ecofactual data has mounted, however, the analytical tools required for its synthesis across space and time have not always kept pace. While recent attention has been devoted to spatial aspects of meta-analysis, particularly through increasingly sophisticated applications of GIS (see e.g. Livarda and Orengo 2015; McKechnie and Moss 2016), the methodological and statistical challenges of chronological synthesis have been somewhat neglected.Nowhere is this issue more acute than for urban archaeological sites. A typical combination of complex, well-dated stratigraphy, rich organic remains, and multiple small-to medium-scale excavations often leads to an abundance of small datasets with cross-cutting phasing and varied chronological resolution. Separately, many of these datasets are of limited value; together they can represent the environmental and socio-economic history of a city. The quality of excavation and documentation in this context is often very high, but the resources available for subsequent a...

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“…Thus, archaeologists are consistently interested in the chemical groups that compositional analyses of ceramics suggest. Yet, it is not always clear that the definition of such chemical groups may be dependent on the way compositional data are transformed (Michelaki and Hancock, 2011), on the particular data exploration method selected (Baxter and Freestone, 2006) and even on the specific elements selected for consideration (Baxter and Jackson, 2001). Although some archaeometrists and statisticians consider such dependence obvious, the issue is rarely addressed clearly in the literature.…”

Section: Introductionmentioning

confidence: 90%

On establishing ceramic chemical groups: exploring the influence of data analysis methods and the role of the elements chosen in analysis

Michelaki

Hughes

Hancock

2013

Open J Archaeometry

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Since the 1970s, archaeologists have increasingly depended on archaeometric rather than strictly stylistic data to explore questions of ceramic provenance and technology, and, by extension, trade, exchange, social networks and even identity. It is accepted as obvious by some archaeometrists and statisticians that the results of the analyses of compositional data may be dependent on the format of the data used, on the data exploration method employed and, in the case of multivariate analyses, even on the number of elements considered. However, this is rarely articulated clearly in publications, making it less obvious to archaeologists. In this short paper, we reexamine compositional data from a collection of bricks, tiles and ceramics from Hill Hall, near Epping in Essex, England, as a case study to show how the method of data exploration used and the number of elements considered in multivariate analyses of compositional data can affect the sorting of ceramic samples into chemical groups. We compare bivariate data splitting (BDS) with principal component analysis (PCA) and centered log ratio-principal component analysis (CLR-PCA) of different unstandardized data formats [original concentration data and logarithmically transformed (i.e. log 10 data)], using different numbers of elements. We confirm that PCA, in its various forms, is quite sensitive to the numbers and types of elements used in data analysis.

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Log‐ratio Compositional Data Analysis in Archaeometry*

Cited by 99 publications

References 18 publications

On the provenance and manufacture of red-slipped fine ware from ancient Cassope (NW Greece): evidence by X-ray analytical methods

On the provenance and manufacture of red-slipped fine ware from ancient Cassope (NW Greece): evidence by X-ray analytical methods

Catch Per Unit Research Effort: Sampling Intensity, Chronological Uncertainty, and the Onset of Marine Fish Consumption in Historic London

On establishing ceramic chemical groups: exploring the influence of data analysis methods and the role of the elements chosen in analysis

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