The INCB-WHO Guide on Estimating Requirements for Substances under International Control is intended to assist competent national authorities in identifying methods for calculating the quantities of controlled substances required for medical and scientific purposes. At the same time, it will help those authorities to prepare the estimates and assessments of annual requirements for controlled substances that countries are required to furnish to the International Narcotics Control Board (INCB). It describes the system of estimates and assessments and the various methods commonly used to quantify the requirements of controlled substances for medical and scientific purposes. It also provides an overview of the major issues that need to be considered in order to apply these methods accurately.

Several methods have been developed for calculating the requirements of controlled substances for medical purposes (see section II.B and annex I). No single method should be systematically recommended for all countries because the choice of method depends on the specific conditions in each country. This Guide has been prepared to help competent national authorities:

a) To identify the most appropriate method (or methods);

b) To improve the accuracy of the method (or methods) in use;

c) To calculate estimates and assessments of controlled substances to be furnished to INCB;

d) To train staff working in drug regulatory administrations.