Although the participants liked the program, its measured outcomes were negative

They meant well.  Then as now.  From A Thirty-Year Follow-up of Treatment Effects by Joann McCord.  The original study ran from 1939 to 1944.

In 1935, Richard Clark Cabot instigated one of the most imaginative and exciting programs ever designed in hopes of preventing delinquency. A social philosopher as well as physician, Dr. Cabot established a program that both avoided stigmatizing participants and permitted follow-up evaluation. 

Several hundred boys from densely populated, factory-dominated areas of eastern Massachusetts were included in the project, known as the Cambridge-Somerville Youth Study. Schools, welfare agencies, churches, and the police recommended both "difficult" and "average" youngsters to the program. These boys and their families were given physical examinations and were interviewed by social workers who then rated each boy in such a way as to allow a selection committee to designate delinquency-prediction scores. In addition to giving delinquency-prediction scores, the selection committee studied each boy's records in order to identify pairs who were similar in age, delinquency-prone histories, family background, and home environments. By the toss of a coin, one member of each pair was assigned to the group that would receive treatment.

The treatment program began in 1939, when the boys were between S and 13 years old. Their median age was 10 1/2. Except for those dropped from the program because of a counselor shortage in 1941, treatment continued for an average of 5 years. Counselors assigned to each family visited, on the average, twice a month. They encouraged families to call on the program for assistance. Family problems became the focus of attention for approximately one third of the treatment group.  Over half of the boys were tutored in academic subjects; over 100 received medical or psychiatric attention; one fourth were sent to summer camps; and most were brought into contact with the Boy Scouts, the YMCA, and other community programs. The control group, meanwhile, participated only through providing information about themselves. Both groups, it should be remembered, contained boys referred as "average" and boys considered "difficult." 

 

The present study compares the 253 men who had been in the treatment program after 1942 with the 253 "matched mates" assigned to the control group.

I am not sure I have come across this before.  Sounds like what is still being recommended today.  1) Intervene, 2) Provide wrap-around social, health, and academic resources, 3) anticipate good life outcomes.

The actual results as measured thirty years later?  From the Abstract.

Over 500 men, half of whom had been randomly assigned to a treatment program that lasted approximately 5 years, were traced 30 years after termination of the project. Although subjective evaluations of the program by those - who received its benefits would suggest that the intervention had been helpful, comparisons between the treatment and control groups indicate that the program had negative side effects as measured by criminal behavior, death, disease, occupational status, and job satisfaction. Several possible processes are suggested in explanation of these findings.

Interesting that the participants thought that the program helped when empirically it actually hurt.  

And interesting that a program plausibly designed to improve outcomes somehow ended up causing negative outcomes.

This in response to someone's clip from Warriors and Worriers by Joyce F. Benenson, page 61.

Even boys from very stable families become more aggressive if they go to preschool. The same effect occurs with older boys. When well-intentioned psychologists attempted to reduce aggression by partnering aggressive boys with nonaggressive boys, the study backfired: All the boys came out more aggressive [35]. Male aggression blossoms around male peers if no adult counters their influence.

 Got to have males in the family to teach young boys how to be men.  Fascinating to see these good intentions come a cropper.  The diligence and attention to run such programs is not present.