- The document discusses using web data to estimate the contribution of the sex industry to UK GDP, which was previously estimated at £5.314 billion or 0.4% of GDP based on a 2004 study. - The author built an API to scrape data from the AdultWork sex worker directory and found that 40% of sex workers listed are men, not accounted for in prior estimates. - Recalculating to include male sex workers increases the estimated contribution to £8.856 billion or 0.6% of UK GDP, adding £3.542 billion to the previous estimate.

1. Andrew Fogg
Sex, drugs and data:
UK GDP Redux
Friday 27 June 2014
presented by

2. this talk is mainly about sex

3. and data

4. no drugs I am afraid

5. let’s start with a question

6. how much does prostitution contribute
to the UK economy?

7. £1bn?

8. £2bn?

9. £5.314bn

10. 0.4% GDP

11. £5.314bn
that is a big number

12. bigger than the entire economy of Moldova

13. bigger than 28% of global economies

14. but it would only buy 45% of WhatsApp

16. restatement of accounts in line with
EU accounting guidelines

17. “illegal transactions to which all parties consent
should be included in national accounts”

18. this includes prostitution and sale of illegal drugs

19. how did the ONS calculate that number for
prostitution?

20. very simple

21. there are lots of assumptions
and the number of prostitutes relies on one study

22. tried to count all the prostitutes in London
over 6 months in 2004

23. phoned every brothel and escort agency
they could find advertised

24. 7,000 (+115)
estimated count of off-street prostitutes in London
(plus estimate of on-street prostitutes from police)

25. scaled out to the UK using population statistics

26. how reliable is that number?
especially the scaling assumption?

27. time to look at some web data

28. many activities associated with
prostitution are illegal in the UK

29. but paying for sex is actually legal

30. as a result prostitution sits in a grey area and is
widely marketed on the web

31. built an API to AdultWork directory using Import.io

32. AdultWork is ranked 174 top site in UK by Alexa

33. searched for all sex workers based in the UK and
downloaded the data

34. categorised each sex worker by location
(London / not London)

35. counted the number of London based prostitutes
and estimated the UK total using scale assumption

36. then counted the number of UK based
prostitutes on AdultWork

37. it seems that the scaling assumption is reasonable

38. so the ONS numbers are good?

39. not quite

40. what is wrong with this picture?

41. there are no men

42. “no information is included regarding
men working in the sex industry”

43. 40% of the prostitutes on AdultWork are men
(in London and across UK)

44. recalculating GDP to take into account male
prostitution gives a dramatic increase

45. £8.856bn
new number

46. 0.6% GDP

47. the new total is bigger than the
entire economy of Iceland

48. bigger than 37% of global economies

49. but it would still only buy 75% of WhatsApp

50. this is only a preliminary analysis

51. but i just added £3.542bn to the UK economy

52. plan to investigate further by examining the price
per visit (data is also available on the web)

53. benefit of using web data for this kind of analysis is
that it is up to date and can be tracked

54. learn more at http://www.import.io