The objectives of the CBA were to: estimate the costs of treatment; descriptively compare the costs and outcomes of drug treatment overall and by treatment centre; estimate the monetary value of the outcomes measured by the DTORS and the overall net benefit of treatment.

The economic evaluation used cost consequences analysis to descriptively compare the costs and outcomes of drug treatment. Cost benefit analysis was used to estimate the net benefit (cost) of drug treatment.

The cost estimates included the fixed and variable costs of the treatment centres, the costs of services accessed or used by service users and families as part of treatment or as a consequence of treatment. These data were collected from a review of centre accounting and information systems, service user records (where these existed) and interviews and questionnaires completed by care and support staff and service users. The outcomes included:

• Quality adjusted life years;
• Engagement in drug related behaviours;
• Severity of drug dependence;
• Offending behaviour;
• Employment.

Existing literature and stated preference techniques will be used to estimate the monetary value of these outcomes.