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Identifying patterns of distribution in olive oil trade 1 Xavier - - PowerPoint PPT Presentation
Identifying patterns of distribution in olive oil trade 1 Xavier - - PowerPoint PPT Presentation
Identifying patterns of distribution in olive oil trade 1 Xavier Rubio-Campillo xavier.rubio@ed.ac.uk @xrubiocampillo A wishlist for Roman economy A wishlist for Roman economy A wishlist for Roman economy A wishlist for Roman economy
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A wishlist for Roman economy
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A wishlist for Roman economy
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A wishlist for Roman economy
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Quantifying Roman economy
Broekaert, W. (2011). Oil for Rome during the second and third century AD: a confrontation of archaeological records and the Historia Augusta. Mnemosyne, 64(4), 591–623.
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Quantifying Roman economy
Temin, P., 2013. The Roman Market Economy. Princeton University Press, p.75
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Quantifying Roman economy Low sample size
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Quantifying Roman economy Low sample size Archaeological biases
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Quantifying Roman economy Low sample size Archaeological biases Multiple proxies
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Quantifying Roman economy Low sample size High uncertainty Archaeological biases Multiple proxies
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The challenges of the fjeld We need to use methods able to tackle these challenges We need informative proxies of economic activity
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Amphoric stamps as proxies
Previous research suggests that the frequency distribution
- f amphoric stamps is a good proxy of economic activities
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Amphoric stamps as proxies
Previous research suggests that the frequency distribution
- f amphoric stamps is a good proxy of economic activities
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Amphoric stamps as proxies
Previous research suggests that the frequency distribution
- f amphoric stamps is a good proxy of economic activities
Rubio-Campillo, X. et al. In press. Bayesian analysis and free market trade within the Roman Empire, Antiquity.
“Our results show that the size of the economic agents involved in this massive market followed a power-law distribution. As a consequence, the model selection framework strongly indicates the presence of free market structures within the olive oil production feeding the city of Rome.”
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Amphoric stamps as proxies
Previous research suggests that the frequency distribution
- f amphoric stamps is a good proxy of economic activities
Rubio-Campillo, X. et al. In press. Bayesian analysis and free market trade within the Roman Empire, Antiquity.
“Our results show that the size of the economic agents involved in this massive market followed a power-law distribution. As a consequence, the model selection framework strongly indicates the presence of free market structures within the olive oil production feeding the city of Rome.”
What about the rest of the Roman empire?
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Research questions
Is there a relation between the distribution of amphoric stamps and the provincial structure?
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Research questions
Is there a relation between the distribution of amphoric stamps and the provincial structure?
Q1: Do sites in the same province have similar stamps?
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Research questions
Is there a relation between the distribution of amphoric stamps and the provincial structure?
Q1: Do sites in the same province have similar stamps? Q2: What provinces have similar stamps?
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The distribution of amphoric stamps
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Identifying province structure
Idea: Two sites of the same province will have more similar stamps than two sites located at difgerent provinces
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Identifying province structure
Idea: Two sites of the same province will have more similar stamps than two sites located at difgerent provinces
There is no relation between the province
- f a site and its stamps
Null hypothesis
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Identifying province structure
We need to...
...quantify the similarity of stamps
There is no relation between the province
- f a site and its stamps
Null hypothesis
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Identifying province structure
We need to...
...quantify the similarity of stamps ...create a distance matrix of similarities between sites
There is no relation between the province
- f a site and its stamps
Null hypothesis
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Identifying province structure
We need to...
...quantify the similarity of stamps ...create a distance matrix of similarities between sites ...compare similarities within/between provinces
There is no relation between the province
- f a site and its stamps
Null hypothesis
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Quantifying similarity
We will use the Jaccard distance:
2 sites have exactly the same stamps → 2 sites have completely difgerent stamps 1 →
PNN QCM VIRG SRN Emporiae 1 1 1 Massalia 1 1 1 1 PNN QCM VIRG SRN Emporiae 1 1 1 Vindolanda 1 1
Jaccard distance: 0.25 Jaccard distance: 0.75
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Multi-Response Permutation Procedure
MRPP allows us to assess if a specifjc grouping is linked to a dissimilarity matrix It evaluates statistical signifjcant difgerences between:
the mean distance within each group the mean distance for the entire dataset weighted by group sizes
Rodgers, P. (1987). Multi-Response permutation procedures. Computer and Quantitative Methods in Archaeology, 7957, 45–54. McCune, B., & Grace, J. (2002). MRPP (Multi-response Permutation Procedures) and related techniques. Analysis of Ecological Communities: MjM Software Design, Gleneden Beach, Oregon, USA, 188–197.
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MRPP results
Mean distances average within provinces 0.995 between provinces 0.997 Efgect 0.002 Signifjcance: 0.001
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MRPP results
Mean distances average within provinces 0.995 between provinces 0.997 Efgect 0.002 Signifjcance: 0.001
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MRPP revisited
P-value < 0.01 for all tests
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MRPP revisited
P-value < 0.01 for all tests
n=1
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MRPP revisited
P-value < 0.01 for all tests
n=25
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MRPP revisited
P-value < 0.01 for all tests
What provinces have similar stamps?
n=25
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Similarity between provinces
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Similarity between provinces
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Similarity between provinces
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Discussion
There is a relation between the province of a site and its stamps
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Discussion
There is a relation between the province of a site and its stamps Stamp similarity is linked to common boundaries
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Discussion
There is a relation between the province of a site and its stamps Stamp similarity is linked to common boundaries Exceptions can answer to political dynamics
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Discussion
There is a relation between the province of a site and its stamps Stamp similarity is linked to common boundaries Exceptions can answer to political dynamics
Trade routes seem to emerge from province similarity
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Concluding remarks
The framework can test new hypotheses
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Concluding remarks
The framework can test new hypotheses
Riverine transport Atlantic vs Mediterranean
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Concluding remarks
The framework can test new hypotheses
Independent military network Riverine transport Atlantic vs Mediterranean
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Concluding remarks
The framework can test new hypotheses
Independent military network Riverine transport Atlantic vs Mediterranean Distribution of other goods
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Concluding remarks
The framework can test new hypotheses A move from Descriptive statistics to Hypothesis Testing would improve our interpretations
Independent military network Riverine transport Atlantic vs Mediterranean Distribution of other goods
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Concluding remarks
The framework can test new hypotheses A move from Descriptive statistics to Hypothesis Testing would improve our interpretations Any quantitative analysis should integrate the complexities
- f the archaeological record
Independent military network Riverine transport Atlantic vs Mediterranean Distribution of other goods
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@xrubiocampillo
Thank you!
xavier.rubio@ed.ac.uk «Humans are pattern-seeking story-telling animals, and we are quite adept at telling stories about patterns, whether they exist or not» Michael Shermer
Source code and dataset available at: https://github.com/xrubio/ecologyStamps