Abstract
Evaluation of treatment programs for drug-dependents in Spain. Studies designed to evaluate programmes for the treatment of drug-dependency are of obvious interest and relevance at the present time. The development of a research protocol to deal with the most common methodological difficulties in this type of study is a priority, not only for researchers and professionals, but also for the administrations, institutions and services involved. It is with this objective that studies carried out in Spain up to the present time are reviewed, analysing the methodological problems most frequently encountered. Finally, some recommendations are made, with the aim of minimising the effects of the problems and increasing the internal and external validity of evaluations.
