The National Opioid Pharmacotherapy Statistics Annual Data (NOPSAD) collection provides national data on women being treated with medication (pharmacotherapy) for their dependence on opioid drugs such as heroin. It also provides statistics on those prescribing the medication and where it was dispensed. The data are based on a ‘snapshot’ period—usually a day—in June 2009. Snapshot data provide a glimpse of pharmacotherapy treatment activity on a specified day, but do not capture the total estimated activity for any given year. However, snapshot data are considered to be a good representation of the total client base.