Historically this has meant that measured productivity has grown more slowly in public services than in other parts of the economy--the so-called 'Baumol effect'

O'Connor mounting pressure on state finances by public-sector trade unions claiming the same wages and benefits as workers in private industry and thereby exposing the state to the ‘cost disease’ of the service sector

Such a bias arises in an acute form in what is known as the Baumol effect, after the US economist William J. Baumol, who argued that productivity grows faster in certain sectors than in others, and that in some sectors there was no scope for producing more output per person.

Baumol's cost disease means that the cost of many critical sectors in an economy tends to rise over time

The problem that Baumol and Bowen identified was subtler than that: They named a condition called "cost disease." While classical music hasn't grown any more productive, the cost of producing it keeps increasing.