I heard one of speeches talking about a study that was evidence and proof of the greatness, and benefits it brings. So, I researched it and found it. Here it is. He did however say studies plural, and I found a singular!

Childhood and Society

This book by Erik Erikson, published in 1950, is a classic because it was one of the first to show how Sigmund Freud's theory of infantile sexuality could be broadened in the light of fieldwork in cultural anthropology and sociological studies.

http://www.enotes.com/childhood-society-...

One of the greatest challenges for political observers is determining which threat to America's freedom and longevity present the greatest concern. Universal Head Start may be the quiet villain that undermines our future. Not only has head start consistently failed to produce results, but more importantly, the bureaucratic minds can tailor early learning programs to influence a long-term bias toward acceptance of bureaucratic statism.