The indicators are refined for each drug and then combined into one index that can be followed over time. A data set included in the DAI must meet several criteria: cause and effect relation between availability and the indicator, stability of the relationship between availability and the indicator over time, objective measurement of the indicator, and nonexcessive indicator variability. The indicators include price, purity, number of seizures during routine investigations, average amount of drugs seized during routine investigations, number of laboratory submissions, percentage of total laboratory submissions, cocaine, and crack cocaine. The DAI is applied to analyze marijuana, cocaine, and crack cocaine. The analysis shows that the popularity and use of marijuana is on the rise in Maryland, that cocaine availability will increase in the future, and that crack cocaine availability is increasing. 3 tables and 7 charts