To know what impact a prevention program may have made, you often have to light the blue touch-paper, stand back – and wait.

J. David Hawkins and his colleagues from the University of Washington have waited eleven years to see whether their Seattle Social Development Project (SSDP) benefited children who participated when they were in elementary school.

SSDP is an ambitious program designed to strengthen children’s connections to their families and schools and to prevent health and behavior problems, such as delinquency and drug abuse, later in life.

In 1995 the basic idea was to help children to set out and stay on a positive path. The program’s components included opportunities to be involved in prosocial activities with other well-behaved kids and to be rewarded for good behavior. At the same time, SSDP aimed to restrict opportunities for antisocial behavior and exposure to poorly-behaved peers.

An accumulation of positive experiences and the dearth of negative ones are supposed to result in a wide range of academic, behavioral, and emotional benefits. To nudge kids along the right path, SSDP also worked to improve teachers’ and parents’ skills in managing behavior and promoting self-control and social competencies.

The best way to assess long-term impact is to compare results for students randomly chosen to participate in an intervention like SSDP to students randomly chosen to receive no special intervention.

Hawkins and his colleagues, who report their 11-year findings in the new journal Victims and Offenders, did not do not make such a telling assessment, but they did compare three groups who came from similar family backgrounds: children who participated in SSDP for the entire length of the program (first through sixth grade), children who participated for a shorter period, and children who did not participate at all. Altogether, 808 children from 18 urban schools in Seattle, Washington were involved.

The Washington team say that the data collected from participants and their teachers at the end of second grade, at the beginning of fifth grade, at the end of sixth grade, at age 18, and at age 21 suggest that the program had myriad positive effects.

By the age of 21, participants were functioning better at school or work, had better emotional and mental health and fewer risky sexual practices. Additionally, they were less likely than those in the other groups to be involved in a variety of crimes or to have sold drugs in the previous year.

Similarly, those who participated for more years generally experienced more benefits than those who were in the program for few years.

• “Promoting social development and preventing health and behavior problems during the elementary grades: Results from the Seattle Social Development Project” by J. David Hawkins, Brian H. Smith, Karl G. Hill, Rick Kosterman, Richard F. Catalano, and Robert D. Abbott in Victims & Offenders, Volume 2, Issue 2 April 2007 , pages 161 – 181.