PRESS RELEASE: Misleading and Irresponsible Drug Prevalence Statistics

MISLEADING AND IRRESPONSIBLE DRUG PREVALENCE STATISTICS: the Global Commission on Drugs Policy claims for rising drug use are incorrect

Were Kofi Annan and the other signatories to the Global Commission on Drugs Policy Report misled by the Report’s exaggerated claim of rising global drug use?

This is the question asked by Kathy Gyngell in ‘Misleading and irresponsible drug prevalence statistics’ a CPS Factsheet released today. This is particularly timely, given that the Liberal Democrats, on Sunday 18th September, voted to back a conference motion which advocates decriminalisation of drug possession and legalised regulation of cannabis.

Estimates published by the recent Global Commission on Drug Policy Report led to extensive media reporting of a substantial increase in drug use globally over the last ten years and thus of a failed ‘war on drugs’. Their estimates were attributed to UN data. Having contacted the UNODC, we have since found that (in UNODC’s own words) “the GC calculated those figures based on flawed methodology.”

The Global Commission reported that there had been a 34.5% rise in opiates, a 25.7% rise in cocaine and an 8.5% rise in cannabis consumption between 1998 and 2008, but the figures were presented without source in the Commission’s report. The UNODC helpfully assisted us in tracking down where these numbers came from: the estimate for 1998 came from the UNODC 2002 Global Illicit Drug Trends, and those for 2008 from the UNODC 2010 World Drug Report.

However, the UNODC has since communicated the statistical inaccuracies of the information presented. Below, we present their findings in quotes:

1) “the 2008 figures used in the paper, they appear to have been calculated by the authors of the paper, as mid-point of the statistical ranges presented in UNODC 2010 World Drug Report. It is not correct to assume that the mid-point of statistical range necessarily represents the best point estimate. As a matter of fact, in the same issue of the World Drug Report, UNODC did present best estimates for cocaine and opiate use, with 15.42 million users for cocaine (as opposed to 17.35 million in the commission’s report), and to 15.9 million for opiate users (as opposed to 17.2 million in the commission’s report)”


2) “Based on UNODC published best estimates of the number of cocaine and opiate users, the number of annual users for opiates increased, between 1998 and 2008, by 19.6% (as opposed to 34.5 % as presented in the Global Commission’s report) and by 18.7 % for cocaine (as opposed to 27% as presented in the Global Commission’s report).” Thus, the increase in the absolute numbers have increased much less quickly than implied by the Global Commission. See Table 2 below.

3) “During the period 1998-2008, the world population aged 15-64 grew by 685 million people, or + 18.5 %. Even if the prevalence of drug use remains the same, the increase in population would mean that the absolute number of users would increase proportionally. This important fact was not taken into account by the authors of the Global Commission’s paper.” The Global Commission completely ignored to control for population increase – the huge increase in the world’s population was always likely to force upward pressure on the consumption of drugs.

4) “Based on UNODC published best estimates of the number of cocaine and opiate users, the prevalence rates for annual use in the population age 15-64 remained stable at around 0.35% for opiates and 0.36 % for cocaine between 1998 and 2008.” When population growth is controlled for, prevalence has remained essentially the same. 

5) “UNODC did not present a best estimate for the number of cannabis users, but one can note that the increase calculated in the Global Commission paper (+8.5%) is actually below the 18-64 age group population increase (+18.5 %) which would translate in a decline of the prevalence rate of use for cannabis.”


Given this information, it is unclear whether high-profile signatories to the Global Commission would have been so willing to support the group, had they known of the misuse of statistics. It is clear that, in terms of the prevalence of drug consumption, the ‘War on Drugs’ has not been a complete failure. In fact annual global drug prevalence has remained largely stable at 4.8% (of the global adult population) in recent years, while there has been a 75% drop in US cocaine consumption since 1988 (from 660 to 165 tons in 2008).

The Centre for Policy Studies therefore calls for:

  • A stop to the use of these flawed statistics.
  • Genuine evidence-based policy making on drugs.
  • Clarification from the Global Commission as to the justification for their presented evidence.

Kathy Gyngell, CPS Research Fellow, said, “In the febrile atmosphere of drugs policy debate the uncritical reporting of ‘statistics’ to suit an argument has, in recent months, taken precedence over checking their source or validity. Yet statistics are only as valid as the sources from which they are drawn, as John Kay warned recently (Sex, lies and pitfalls of overblown statistics, FT August 23 2011). The newly emerged Global Commission on Drug Policy has  proved to be neither a valid or reliable source.”

The Factsheet can be downloaded from here.

Kathy Gyngell is available for comment and can be contacted through the CPS 0207 222 44 88.


  1. Misleading statistics is a Factsheet released by the Centre for Policy Studies on Monday 19th September 2011.
  2. Kathy Gyngell chaired and authored the Addictions Reports of the Social Justice Policy Review for the Conservative Party, published in Breakdown Britain in December 2006 and Breakthrough Britain in July 2007. She is chair of the newly formed Addictions Policy Forum at the CPS and has authored ‘The Phoney war on Drugs’ CPS 2009 and ‘Breaking the Habit – why the state should stop dealing drugs and doing rehab’ CPS 2011.

Date Added: Wednesday 21st September 2011