Following up on the attention paid to the new Bill Gormley study of the effects of the state's $7,000 per year prekindergarten program I came across this ABC television report from May. It shows the power of television when done well. I particularly liked the video of a kindergartner who had attended pre-k writing letters (steady, clear, nicely formed) while, on a split screen, a kindergartner who had not gone to pre-k tried to do the same. (wobbly lines, some unrecognizable letters, slower).

The ABC report quoted candidate Obama saying he supported pre-k because it would return $10 for every dollar invested. I've now come across economic returns estimates of between $2.36 and $17 for each dollar invested. (See Clive Belfield's report as well as this oneby Steve Aos at the Washington State Institute for Public Policy.)

Not sure where Obama's number comes from but what's important is that each of these studies makes different assumptions, uses different methodologies for evaluating costs and savings, and covers different time periods. Point is that even the lowest estimate shows a better than one-to-one return. That return has to be evaluated against the returns from other social interventions, some of which are highly targeted and others, such as public schooling in general, that are universal.