David and Goliath: Underdogs, Misfits, and the Art of Battling Giants

experiments have many advantages over
formal experiments. So what happens if
you use the natural experiment of
Connecticut—and compare the year-to-
year results of every child who happens
to have been in a small class with the
results of those who happened to have
come along in years with lots of kids?
The economist Caroline Hoxby has done
just that, looking at every elementary
school in the state of Connecticut, and
here’s what she found: Nothing! “There
are many studies that say they can’t find
a statistically significant effect of some
policy change,” Hoxby says. “That
doesn’t mean that there wasn’t an effect.
It just means that they couldn’t find it in