Summary

The aim of the present project was to provide a comprehensive, standardized set of measures for the evaluation of opiate treatment. In constructing the Opiate Treatment Index (OTI) as a comprehensive evaluative tool, the authors considered that a number of criteria should be met:

1. The primary consideration was that the index should be multi-dimensional in nature. Clearly, the aims of opiate treatments extend beyond the cessation or reduction of drug use. Opiate use is associated with a broad range of health, legal and social problems. Furthermore, there is evidence that the problems associated with opiate use are relatively independent (e.g. McLellan et al, 1981). An assessment instrument should reflect this heterogeneity in its structure.
2. The instrument should be based upon objective data rather than on the impressions of interviewers. This is to avoid the problems engendered by the differing criteria for "success" employed by different researchers. What such objective scales should provide are data on the recent behaviour of clients in a number of outcome domains. Obviously the interpretation of the data regarding success or failure will depend upon the ideology of the researcher. This should, however, be independent of data collection.
3. The variables employed should, if possible, be continuous rather than categorical, in order to maximize the sensitivity of the instrument to actual behaviour change.
4. To be of maximum utility, such an instrument should have both clinical and research applications. The scales should provide information which is of interest to clinical staff, as well as providing global research data.
5. To be of use in clinical settings, an assessment instrument should be relatively brief and easy to administer. The instrument must be able to be employed by both medical and non-medical personnel, given the diversity of staff engaged in both the clinical and research aspects of opiate treatment.
6. Such an instrument should be of proven reliability and validity.

The OTI was constructed to meet these criteria. A complete description of the OTI and data concerning its reliability and validity can be found in Darke et al (1992). The OTI has also subsequently been successfully tested for reliability and validity in the United Kingdom (Adelekan et al, 1996a) and New Zealand (Deering & Sellman, 1996).

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• NDARC Technical Report No. 011 (1991) - The Opiate Treatment Index (OTI) Manual