How many people are metal-detecting and how many cultural objects are they finding?

On Friday, (open-access) Cogent Social Sciences published my estimation of how many people are metal-detecting, how many hours they’re doing it and how many cultural objects they’re finding, whether they’re supplying their own private collections or whether they’re selling into the antiquities trade, supplying the licit/illicit market. Since it’s 21,084 words, excluding the bibliography, I thought it might help to post some notes and some extracts, with the data on the number of detectorists and the number of finds.

a note on territories, here and elsewhere

This article covers Australia; Austria; Belgium, including the distinct jurisdiction of Flanders; Canada; Denmark; Ireland; the Netherlands; New Zealand; the United Kingdom, encompassing the separate jurisdictions of England and Wales, Northern Ireland, and Scotland; and the United States.

However, I’ve been using the same methods (as well as adapted ones and different ones) to collect data on territories around the world. Perhaps surprisingly, considering how little quantitative analysis has been done, there is a lot of quantitative data. It’s actually difficult to process and publish everything.

As I noted, this article is 21,084 words and it only covers 12 legal territories within 10 states out of 206 (recognised or unrecognised). Luckily for me, not all of the searches have been equally successful. Now that I’ve published this proof-of-concept study, I’ll try to publish another proof-of-concept study for other methods of estimation, then the rest of the data in geographically-coherent sets, whether by continent or continental region.

It may still be too much. A half-written chapter on Asia is already more than 20,000 words. So, perhaps I’ll post the complete evidence of failed searches on the blog, then discuss it in the introductions to publications of material evidence from successful searches. Hopefully, they’ll form a useful evidence base for cultural property criminology. I’ll start off with the statistics on extraction, then move on to the “fun” stuff on supply. Anyway, back to the published evidence…

contents

The article:

  • considers the Portable Antiquities Scheme (PAS) for England and Wales and the Artefact Erosion Counter from Heritage Action;
  • explains the method for estimating the scale of metal-detecting activity from open data;
  • discusses the difficulty of inferring the real-life activity of online communities;
  • provides evidence and interpretation of the scale of metal-detecting activity by territory, including the legal regulations of each territory, which help to determine numbers of licit detectorists and numbers of illicit detectorists;
  • explains the method for estimating the intensity of metal-detecting activity from open data;
  • presents evidence and interpretation of the intensity of metal-detecting activity;
  • explains the method of estimating the quantity of metal-detected cultural property from the rate of recovery;
  • explains the method of (under)estimating the quantity of metal-detected cultural property from the rate of reporting; and
  • applies to rate of recovery to estimate how many cultural objects are extracted by metal detectorists every year; then,
  • draws conclusions on
    • measures and applicability,
    • secure underestimates and
    • the quantity of unscientifically extracted cultural assets and the effectiveness of regulation.

searches for the scale of metal-detecting activity

Web searches included:
“000 detectorists”;
“000 * detectorists”;
“thousand detectorists”;
“thousand * detectorists”;
“000 detecting” (which allowed for references to “detecting hobbyists”, etc.);
“000 * detecting”;
“000 detector” (which allowed for references to “detector users”, etc.);
“000 * detector”;
“metal detecting” forum in the relevant country code top-level (internet) domains (ccTLDs); and
“metal detecting” forum and the name of the relevant territory.

Using open-ended search terms, in order to allow for variations in vocabulary and grammar, Facebook searches included:
metal detecting (without speech marks) and the name of the relevant territory; and
treasure hunting (without speech marks) and the name of the relevant territory.

It should be noted that all of the data in the present analysis is open data, which has been willingly provided publicly by its sources; it has also been archived, so it remains available for reanalysis, reproduction and/or reinterpretation.

searches for the intensity of metal-detecting activity

In order to find data and analyses of non-professional, licit and illicit use of metal detectors to find historical and cultural goods, a range of Google Scholar searches were conducted:
“metal detecting” and “illicit antiquities”;
“metal detectors” and “illicit antiquities”;
“metal detecting”, “antiquities” and looting;
“metal detectors”, “antiquities” and looting;
“metal detecting” and ethnography;
“metal detecting” and poll; and
“metal detecting” and survey.

In order to estimate the intensity of detecting activity, several Google searches were conducted:
“how long”, metal, detecting and forum;
“how many hours” and metal detecting (without speech marks);
“how much time” and “metal detecting”;
“how often” and “metal detect”; and
“how often” and “metal detecting”.

the real-life activity of online communities

The largest identifiable poll… provided albeit imprecise, singular and dated evidence with regard to inactivity. It is not secure evidence, yet it is evidence nonetheless. In this poll, 17 (2.54 per cent) of 668 had never detected and 27 (4.04 per cent) of 668 had never detected regularly, even at a low frequency (Marc, 2004). Hence, in this analysis, 6.58 per cent of members of online forums and social networks were assumed to be inactive; 93.42 per cent were assumed to be active.

tables on the scale of metal-detecting activity

Territory Low estimate Population at time Scale by population
Austria 2,091 8,584,926 1 in 4,106
Ireland 1,128 4,640,703 1 in 4,114
Australia 5,119 23,781,169 1 in 4,646
Denmark 1,209 5,707,251 1 in 4,721
Canada 6,503 35,851,774 1 in 5,513
Belgium 1,680 11,285,721 1 in 6,718
Northern Ireland 225 1,851,600 1 in 8,229
New Zealand 348 4,595,700 1 in 13,206
England and Wales 3,500 54,809,100 1 in 15,660
Total 21,803 151,107,944 1 in 6,931

Table 6: low estimates of illicit metal detecting by population

 

Territory Low estimate Territory in sq km Scale by area
Belgium 1,680 30,528 1 in 18.17
Denmark 1,209 42,916 1 in 35.50
Austria 2,091 83,878 1 in 40.11
England and Wales 3,500 151,140 1 in 43.18
Ireland 1,128 70,283 1 in 62.31
Northern Ireland 225 14,130 1 in 62.80
New Zealand 348 268,000 1 in 770.11
Australia 5,119 7,692,000 1 in 1,502.64
Canada 6,503 9,984,670 1 in 1,535.39
Total 21,803 18,337,545 1 in 841.06

Table 7: low estimates of illicit metal detecting by area (in square kilometres)

 

Territory Low estimate Population at time Scale by population
United States 160,000 306,771,529 1 in 1,917
England and Wales 24,397 57,885,400 1 in 2,373
Netherlands 5,353 16,936,520 1 in 3,164
Scotland 1,447 5,373,000 1 in 3,713
Denmark 1,385 5,707,251 1 in 4,121
Belgium 300 11,285,721 1 in 37,619
Total 192,882 403,959,421 1 in 2,094

Table 8: low estimates of licit metal detecting by population

 

Territory Low estimate Territory in sq km Scale by area
England and Wales 24,397 151,140 1 in 6.20
Netherlands 5,353 41,543 1 in 7.76
Denmark 1,385 42,916 1 in 30.99
United States 160,000 9,372,610 1 in 58.58
Scotland 1,447 78,775 1 in 54.44
Belgium 300 30,528 1 in 101.76
Total 192,882 9,717,512 1 in 50.38

Table 9: low estimates of licit metal detecting by area (in square kilometres)

 

Territory Low estimate Population at time Scale by population
United States 160,000 306,771,529 1 in 1,917
England and Wales 27,897 57,885,400 1 in 2,075
Denmark 2,594 5,707,251 1 in 2,200
Netherlands 5,353 16,936,520 1 in 3,164
Scotland 1,447 5,373,000 1 in 3,713
Austria 2,091 8,584,926 1 in 4,106
Ireland 1,128 4,640,703 1 in 4,114
Australia 5,119 23,781,169 1 in 4,646
Canada 6,503 35,851,774 1 in 5,513
Belgium 1,980 11,285,721 1 in 5,700
Northern Ireland 225 1,851,600 1 in 8,229
New Zealand 348 4,595,700 1 in 13,206
Total 214,685 483,265,293 1 in 2,251

Table 10: low estimates of overall metal detecting by population

 

Territory Low estimate Territory in sq km Scale by area
England and Wales 27,897 151,140 1 in 5.42
Netherlands 5,353 41,543 1 in 7.76
Belgium 1,980 30,528 1 in 15.42
Denmark 2,594 42,916 1 in 16.54
Austria 2,091 83,878 1 in 40.11
United States 160,000 9,372,610 1 in 58.58
Scotland 1,447 78,775 1 in 54.44
Ireland 1,128 70,283 1 in 62.31
Northern Ireland 225 14,130 1 in 62.80
New Zealand 348 268,000 1 in 770.11
Australia 5,119 7,692,000 1 in 1,502.64
Canada 6,503 9,984,670 1 in 1,535.39
Total 214,685 27,830,473 1 in 129.63

Table 11: low estimates of overall metal detecting by area (in square kilometres)

tables on the quantity of metal-detected cultural objects

Territory Low estimate Min avg person-hours per year Min avg number of reportable finds per year Total number of material finds per year
Canada 6,503 1,859,988 576,596 2,045,987
Australia 5,119 1,464,136 453,882 1,610,550
England and Wales 3,500 1,001,070 310,332 1,101,177
Austria 2,091 598,068 185,401 657,875
Belgium 1,680 480,514 148,959 528,565
Denmark 1,209 345,798 107,197 380,378
Ireland 1,128 322,631 100,015 354,894
New Zealand 348 99,535 30,856 109,488
Northern Ireland 225 64,355 19,950 70,790
Total 21,803 6,236,094 1,933,189 6,859,703

Table 26: estimates of minimum average person-hours of illicit detecting per year, number of reportable finds per year and total number of material finds per year, ranked by quantity

 

Territory Low estimate Minimum average person-hours per year Minimum average number of reportable finds per year Total number of material finds per year
United States 160,000 45,763,200 14,186,592 50,339,520
England and Wales 24,397 6,978,030 2,163,189 7,675,833
Netherlands 5,353 1,531,065 474,630 1,684,172
Denmark 1,385 396,138 122,803 435,751
Scotland 1,447 413,871 128,300 455,258
Belgium 300 85,806 26,600 94,387
Total 192,882 55,168,110 17,102,114 60,684,921

Table 27: estimates of minimum average person-hours of licit detecting per year, number of reportable finds per year and total number of material finds per year, ranked by quantity

 

Territory Low estimate Min avg person-hours per year Min avg number of reportable finds per year Total number of material finds per year
United States 160,000 45,763,200 14,186,592 50,339,520
England and Wales 27,897 7,979,100 2,473,521 8,777,010
Canada 6,503 1,859,988 576,596 2,045,987
Netherlands 5,353 1,531,065 474,630 1,684,172
Australia 5,119 1,464,136 453,882 1,610,550
Denmark 2,594 741,936 230,000 816,129
Austria 2,091 598,068 185,401 657,875
Belgium 1,980 566,320 175,559 622,952
Scotland 1,447 413,871 128,300 455,258
Ireland 1,128 322,631 100,015 354,894
New Zealand 348 99,535 30,856 109,488
Northern Ireland 225 64,355 19,950 70,790
Total 214,685 61,404,204 19,035,303 67,544,624

Table 28: estimates of minimum average person-hours of overall detecting per year, number of reportable finds per year and total number of material finds per year, ranked by quantity

the quantity of unscientifically extracted cultural assets and the effectiveness of regulation

Thus, in England and Wales, licit detectorists recover perhaps 2,163,189 recordable objects in one year (table 27), while they report an average of 83,795 objects (PAS, 2016), so perhaps 2,079,394 (96.13 per cent of) recordable objects are not reported; illicit detectorists recover perhaps 310,332 recordable objects (table 26), none of which is reported accurately, though some of those may be laundered by being reported inaccurately. Hence, within this permissive regulatory environment, it appears that licit detectorists cause far more licit cultural harm than illicit detectorists commit criminal damage.

Indeed, 24,397 licit detectorists (or, excluding 4,232-4,328 reporting licit detectorists, 20,069-20,165 non-reporting licit detectorists) cause more licit cultural harm in England and Wales (amongst a population of then 57,885,400) than 18,303 illicit detectorists commit criminal damage in the somewhat restrictive, restrictive or prohibitive regulatory environments of Australia, Austria, Belgium, Canada, Denmark, Ireland, New Zealand and Northern Ireland (amongst a combined population of then 96,298,844).

Likewise, 23,569-23,665 non-reporting licit and illicit detectorists in England and Wales cause more licit cultural harm and criminal damage than 19,003 non-reporting licit and illicit detectorists in Australia, Austria, Belgium, Canada, Denmark, Ireland, New Zealand and Northern Ireland. This suggests that permissive regulation is ineffective in minimising harm to heritage assets, whether in the form of licit misbehaviour or criminal damage.

citation

Hardy, S A. 2017: “Quantitative analysis of open-source data on metal detecting for cultural property: Estimation of the scale and intensity of metal detecting and the quantity of metal-detected cultural goods”. Cogent Social Sciences, Volume 3, Number 1. Available at: https://dx.doi.org/10.1080/23311886.2017.1298397

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