Methodology

Considerable efforts have been made over the last few years to improve the estimates presented in this report. Nonetheless, the data must still be interpreted with caution because of the clandestine nature of drug production, trafficking and abuse. Apart from the ‘hidden’ nature of the phenomenon being measured, the main problems with regard to data relate to the irregularity and incompleteness in reporting. This affects the quantity, quality and comparability of information received. First, the irregular intervals at which some Governments report may result in absence of data in some years but availability in others. The lack of regular data, for which UNODC tries to compensate by reference to other sources, can influence trend patterns. Secondly, submitted questionnaires are not always complete or sufficiently comprehensive. All figures should thus be seen as likely orders of magnitude of the drug problem, but not as precise results. It should be also noted that all figures provided, particularly those of more recent years, are subject to updating.

Sustainable Development Goals:

Good Health and Well-Being