A group called Public Policy Forum has put out a report called The Price of Quality: Estimating the Cost of a Higher Quality Early Care and Education System for Southeast Wisconsin. (PDF)
They now spend $5625 per kid, and they estimate it would cost $11,500 a child for best quality, but you could improve on what they have for $8023 per kid.
They figure they are spending $370 million on child care now (mostly wages), and to get to a high-quality system would take about $700 million. And the dish ran away with the spoon.
The report is interesting. It goes over the various studies about long-term effects of good child care and the cost-benefit analyses done.
It makes a stab at defining high quality, and most of the items are generically good (high education and wages, low ratios, and family support. But then they add, "For three‐ and four‐year olds, use of a professionally developed prekindergarten curriculum." I wonder if they could consider Reggio or High Scope a curriculum or a teaching style. This scares me, as I have said before. I fear canned curricula in general and for preschool in particular. Especially if they specify "professionally developed curriculum" but ignore environmental rating scales or teacher-child interaction evaluations. I guess that's because they were just looking at the things that cost money.
I do believe the main point, though. The actual cost of high-quality child care in California as well as Wisconsin is lots higher than CDE reimburses centers. The Title 5 centers that succeed do so on subsidies and grants.