NPR.

In 2010, the economist John List joined with a couple colleagues to do something that economists

don't normally do.

We built a pre-K program in Chicago Heights from scratch.

John built a name for himself devising these super interesting experiments in the real

world, like creating this pre-school to see what works in education.

And he and his team found really promising results from the school.

The kids' test score shut up, they showed character improvements like greater determination

and grit.

John and his team were excited about all this.

So I tried to scale it.

I went and knocked on the doors of various policymakers.

And each time they would tell me, hmm, John, that's great.

But we don't think your results or your program will scale.

This is often an issue.

Something works in a small experiment, but then when say the government implements it

on a large scale, it doesn't work out so well.

So John got obsessed with the process of scaling.

But when he looked at what had been written about it, what evidence there was already out

there, he was pretty disappointed.

It was more of a kind of art than a science.

So he decided to change that with his new book.

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