The push for bigger public schools and school districts began in earnest at the turn of the 20th century. In 1932, after years of consolidation, there were still 127,531 school districts in the United States. That number dropped precipitously through the early 1970s, when it fell below 20,000. Since that time, the consolidation has continued, though at a far more modest rate. The national count of school districts stood at 14,559 in the 2001-2002 school year (see Graphic 1).

The march toward larger and larger districts has been driven chiefly by a desire for improved efficiency. But by 1980, the nation’s public schools were spending nearly 10 times as much per student as they had in 1920, even after adjusting for inflation.[3] Not surprisingly, researchers eventually noticed that spending was rising despite the growth in average district size and began investigating whether larger districts really did spend less per pupil.[*]

Most of the research on the relationship between school district size and spending has found that there are some "economies of scale" in public education — that larger districts do indeed have lower per-pupil operating expenditures than their smaller counterparts. One example is a 1999 study of Utah public school districts by Kalyan Chakraborty, Basudeb Biswas, and W. Cris Lewis.[4] Similarly, a 2004 report by Vicki Murray of the Arizona-based Goldwater Institute found that consolidation of very small districts would result in modest savings for the taxpayers of that state (though she also concluded that much larger sums would be saved by expanding Arizona’s charter school program).[5]

Several recent studies have concluded, however, that the economic benefits of increasing district size diminish as the size of the district grows, and that there is an optimal size of school district beyond which per-pupil expenditures begin to rise. William Duncombe and John Yinger’s 2003 study of 12 actual consolidations in New York state concluded that doubling the enrollment of a 300-student district is likely to produce a net 22.8 percent savings; that doubling the enrollment of a 1,500-student district is likely to yield a 3.2 percent savings; and that little or no savings are to be expected for mergers of districts already enrolling more than 1,500 students.[6] A good recent summary of the scholarly literature on this topic by Matthew Andrews, Duncombe and Yinger reached the same conclusion, finding, "Sizeable potential cost savings may exist by moving from a very small district (500 or less (sic) pupils) to a district with approximately 2,000 to 4,000 pupils," but the authors noted that per-pupil spending actually starts to go up again when district size reaches 6,000 students.[7]

Graphic 1: Number of U.S. Public School Districts

Graphic 1 - click to enlarge

Source: Tyack, David and Larry Cuban (1995). “Tinkering Toward Utopia.” Cambridge, MA: Harvard University Press, p. 19 (for 1932 datum). And: Snyder, T.D., Tan, A.G., and Hoffman, C.M. (2004). “Digest of Education Statistics 2003, (NCES 2005-025).” Washington, DC: U.S. Department of Education, National Center for Education Statistics, p. 103 (for all other data). Data missing in the original NCES publication.

The fact that earlier study results have not been consistent across states points to the need to gather and analyze state-specific data before embarking on a policy of school district consolidation.

[*] This ex post facto investigation into the actual effects of consolidation is perhaps not as useful as an investigation undertaken before the policy had been aggressively pursued for half a century, but "there you have it," as the British say.