Our urban problems are like the mechanical rabbit at the racetrack, Edward Banfield says, which is set to keep just ahead of the dogs no matter how fast they may run:
Consider the poverty problem, for example. Irving Kristol has pointed out that for nearly a century all studies, in all countries, have concluded that a third, a fourth, or a fifth of the nation in question is below the poverty line.
“Obviously,” he remarks, “if one defines the poverty line as that which places one-fifth of the nation below it, then one-fifth of the nation will always be below the poverty line.” The point is that even if everyone is better off there will be as much poverty as ever, provided that the line is redefined upwards.
Kristol notes that whereas in the depths of the Depression, F.D.R. found only one-third of the nation “ill-housed, ill-clad, ill-nourished,” Leon Keyserling, a former head of the council of Economic Advisors, in 1962 published a book called Poverty and Deprivation in the U.S. — the Plight of Two-Fifths of a Nation.
Similarly, police brutality has gone from meaning cracking skulls to attacking personal dignity with unjustified questioning and searches:
Following Kristol, one can say that if the “police brutality line” is defined as that which places one-fifth of all police behavior below it, then one-fifth of all police behavior will always be brutal.
The school dropout problem is a more striking example:
At the turn of the century, when almost everyone was a dropout, the term and the “problem” did not exist. It was not until the 1960s, when for the first time a majority of boys and girls were graduating from high school and practically all had at least some high school training, that the “dropout problem” became acute.
[...]
Obviously, if one defines the “inadequate amount of schooling line” as that which places one-fifth of all boys and girls below it, then one-fifth of all boys and girls will always be receiving an inadequate amount of schooling.
From The Unheavenly City Revisited (1974).