Methods and definitions

Drug prices

Street prices of cannabis, heroin, cocaine and amphetamine are provided in euros per gram, of LSD in euros per unit/dose, and of ecstasy in Euros per tablet. Data on prices come from a range of different sources the comparability of which is not always known. For example, the type of information systems (police sources, surveys among drug users, etc.) and the sampling strategies used to produce data on the price of illicit drugs at retail level do vary considerably across countries.

Data presented here are submitted to the EMCDDA as being national and annual, as well as referring to the retail level of the market (street level). Some caution is however required when analysing these data as they might, for some of them, present reliability problems. In some cases, they come from local rather than national monitoring systems, and/or from ad hoc non-repeated studies. There is also much uncertainty on the method used to calculate the averages, whether weighted or simple means are being used.

Drug purity/potency

Data on the potency of cannabis products and the purity of heroin (white and brown), cocaine products (cocaine and crack) and amphetamine are presented here.

The potency of cannabis products is equivalent to the tetrahydrocannabinol (THC) content, where THC is the primary active constituent in cannabis. It is expressed in percent of THC. Cannabis potency is provided for herbal cannabis and cannabis resin separately. Whenever possible a further distinction is made between different types of herbal cannabis; however, caution is required here since these distinctions are not always clear.

As with data on prices, the data presented here are submitted to the EMCDDA as being national and annual, as well as referring to the retail level of the market (street level). Some caution in relation to reliability issues is required when analysing these data, since they may come from local or from ad-hoc non-repeated studies rather than national monitoring systems. Some of them are not representative of the retail level and are based on the analysis of all seizures of a drug made and analysed in one country (see part (iii) of the tables for information on this issue). Another source of variation across countries is the type of information systems and the sampling strategies used to produce data on purity/potency. In addition, the way in which ‘average purity/potency’ is calculated is often unclear.

There are analytical difficulties in the precise and accurate determination of the purity/potency of illicit substances; and standards of laboratory analysis might also vary between and within countries.

For more information on cannabis potency see the EMCDDA Insights 6 ‘An overview of cannabis potency in Europe’.