Intervention based on social learning principles is, of course, not new to the treatment of delinquency. A variety of behaviour modification techniques, and in particular token economy schemes have been tried out in the U.S.A. and Canada. Most have been extensively evaluated and found to be far more effective than alternative schemes (Braukmann and Fixsen 1975). Of course, the judicial and welfare context in which Braukmann and Fixsen compare the relative merits of various approaches to delinquency prevention programmes is very different from that operating in the United Kingdom. There are, however, a number of points common to both contexts–there has been very little emphasis on, or funds given to, systematic programme evaluations and those that have been conducted (for example, see reviews by Logan 1972 and Slaikeu 1973) have tended to fall far short of meeting basic research design requirements. Secondly, in both settings perhaps too much emphasis has been placed upon preventing recidivism as a goal of treatment. Braukmann and Fixsen point out that re-conviction as an index of treatment progress does not allow differential qualitative feedback to the adolescent to be closely geared to his progress, and that, in the main, behavioural approaches have tended to fare much better in carrying out scientifically respectable evaluation of their progress in addition to demonstrating a much higher success rate both in terms of recidivism and in terms of more microscopic measures of behavioural improvement. The goal of any behavioural treatment for youngsters in trouble may be simply to extend his choice of behaviour rather than simply prevent recidivism.