Could someone help please.

Some years ago a test was carried out in the states where a number of children (poss 200)
wre used in an experiment.

100 attended a pre school kindergatren & 100 received a general education (without pre school). A number of years later a survey was conducted to see how many of the children had been involved in crime and what if any effect the pre schooling had on the issue.

My question is who conducted this task & when was it carried out

A tuffy but hopefully someone will know the answer

Dave R