Public services are good, but they're not "public goods"

But true public goods are also good and deserve more support

A recent David Zipper column in Bloomberg noted that mass transit is not a public good in the technical economics sense and that this is relevant to arguments about whether cities should invest in $0 fares.

Some of the discussion generated by the piece focused on whether (and how much) it matters that people are using a piece of economics jargon correctl…