It is standard to claim that education generates positive externalities.
For example, Mankiw (2017, Principles of Economics, p. 193):
education also yields positive externalities. One externality is that a more educated population leads to more informed voters, which means better government for everyone. Another externality is that a more educated population tends to result in lower crime rates. A third externality is that a more educated population may encourage the development and dissemination of technological advances, leading to higher productivity and wages for everyone. Because of these three positive externalities, a person may prefer to have neighbors who are well educated.
But do economists (or anyone else) actually have any estimates of the magnitudes of the externalities generated by education?
(For example, Mankiw's "more education leads to better government for everyone" sounds plausible. But has anyone ever tried quantifying this? And if they did, is the effect positive and large? Or might it be near zero or even negative?)