Measuring the harm from illegal drugs using the Drug Harm Index

The Drug Harm Index captures the harms generated by the problematic use of any illegal drug by combining robust national indicators into a single-figure time-series index. The harms include drug-related crime, community perceptions of drug problems, drug nuisance, and the various health consequences that arise from drug abuse (e.g. HIV, overdoses, deaths etc.). The relative importance of each of the harm indicators in the DHI is captured by the economic and social costs that they generate. This follows from work to estimate the economic and social costs of class A drug use, published by the Home Office in 2002. From year to year, the change in the DHI will be due to the growth in the volume of harms (e.g. the number of new HIV cases or the number of drug-related burglaries) and the growth in the unit economic or social cost of the harms (e.g. the rise in the expected cost per new HIV case or the average victim cost of a domestic burglary). Interpreting changes in the DHI requires care, as it is a single measure that summarises much detail. Different categories of harm may evolve differently over time and no single index can fully capture this diversity. It is recommended that the DHI should be considered alongside a basket of individual indicators in order to determine which particular types of harm are becoming dominant, or are being moderated. The DHI does not capture all the harms that illegal drugs might possibly generate, but rather a subset of harm for which robust data are available. As such, this measure is an index indicating change over time, rather than an estimate of the absolute level of harm at any one time. Development of the DHI will be ongoing, as more data and information become available. By the time the DHI is used to monitor the new PSA target it is likely that the drug-related crime indicators will be revised (which might have some impact), and quarterly data will be incorporated. Work to further develop the unit costs of the health indicators and public nuisance is also ongoing.