The Official Journal of
The North Carolina
Sociological Association: A Refereed Web-Based Publication
George H. Conklin,
Chien Ju Huang,
N.C. State University
Volume 2, Number 1
Population Growth, Density and the
Costs of Providing Public Services
Reviewed by George H. Conklin
Background: Many journals have book reviews. However, in the sciences
the most common form of communication is not books, which are out of date
when published, but articles. Many books are based on articles and enlarged
often beyond what is required. However, the opposite is also true: there
are many important articles which address basic issues in the social sciences
that have not been made into books, but perhaps should be. In order to
draw attention to important articles which address basic issues which sociologists
are interested in, Sociation Today will review articles rather than
Our second review article deals with the
core concept of how density affects the human animal . The author of the
article finds a J-curve or non-linear relationship. At very low density
levels, increased population density lowers costs of providing services
such as police protection. But beyond very low levels of density,
as density goes up, so do costs to government. Rapid population growth
also imposes costs on the local population through lower service levels.
Population Growth, Density and the Costs of Providing Public Services,
by Helen F. Ladd in Urban Studies, Vol. 29, No. 2, 1992, pp. 273-295.
One of the oldest hypotheses in the social sciences
is that population density plays a vital role in explaining human behavior.
Following authors such as Louis Wirth (1938) and other work known as the
Chicago School, basic theory holds that as population density increases,
stress on the human animal will also increase. Manifestations of
this include increased levels of social disorder compared to less dense
areas. One measurement of this would be recorded crime levels.
As the population of the United States and indeed
the world as a whole continues to concentrate in cities, local governments
have taken a keen interest in how to pay for the urban overheads necessary
to accommodate the continued concentration of the human population in urban
areas. The costs of providing police services is one area of interest,
as are ways of controlling the costs of urban overheads.
A starting point for Ladd (p. 273) "...is the observation
that we know very little about the average effects of population growth
on local public sector spending." Since the county boundaries of
the USA are fixed, as population increases, so does population density.
But does increased population density increase or decrease costs?
Ladd (p. 274) finds there are two opposite forces at work here. "On
the one hand, higher density is likely to increase per capita spending
as more services, such as refuse collection, must be provided." More
people might increase the harshness of the environment by increasing crime
which would increase public safety costs.
But most planners argue that increased population
density is good because "there are economies of density in the production
of certain services (p. 274)." High density planned development is
supposed result in significant savings to government by reducing both the
capital and operating costs of police, fire and solid waste collection
and disposal services and storm sewers, according to The Real Estate Research
Corporation (1974) and Downing and Gustely (1977). Fixed costs
spread over a larger number of people, it might be argued, would lower
the per capita costs of public services.
To test the actual results of population density
on public services, Ladd looks at data for 247 large counties in 1985 covering
59 per cent of the population of the United States. Piecewise linear
regression is used for analysis (see Figure 1). Piecewise linear
regression assumes a straight line relationship only between any two points
(example b1 and b2), but does not assume that overall a relationship must
The result shown in Figure 1 is a J curve, or a non-linear relationship.
Thus at very low levels of density, for example, population density (the
X axis) can show a decrease in public safety spending. But at higher
levels, the costs show an increase.
Source: Ladd, p. 277.
To avoid a simplistic analysis, Ladd uses many different
measures in her article as controls. Expenditure
variables include spending on current operations, per capita; spending
on public safety, per capita; and capital outlays, per capita 1978. Demand
cost and taste variables are: income, per capita; residential share
of accessed value of property tax base, 1986; manufacturing wage rate (by
state); public school enrollments, per capita; fraction of population below
poverty level, 1979; manufacturing employment per resident; non-manufacturing
jobs per resident; crime rate; population; percentage of population more
than 12 years of education, 1980. Intergovernmental
relation variables are ratio of local direct general expenditure
to state and local direct general expenditure in the county's state; ratio
of local spending on public safety to state and local spending on public
safety in the county's state; federal aid, per capita; state aid, per capita.
dummy variables are East, Midwest, South and West. Density
variables are given the following cutting points of people
per square mile: 0; 250; 500; 1250; 1750; 24,000; or as an alternative
750; 1000; 1500; and 24,000. Population change variables are also
Population growth does not pay for itself.
Ladd finds that "...the major stress on local public spending associated
with a surge in population occurs in the capital, not the current, account
budget (p. 288)." However, as density increases, capital outlays
The same is true for public safety spending.
Population loss costs money, but so does growth at all levels. More
interesting, population density shows a J-shaped relationship. Only
at very low levels of density are costs high, and decline until population
reaches about 250 persons per square mile (see Table 1). Once
the population reaches 250 per square mile any increase in density results
in higher per capita costs for public safety. (As a reference
point, Ladd notes that Wake County, North Carolina, which includes Raleigh,
has an average density of 414 persons per square mile.) Regionally
spending on public safety is lower in the East, Midwest and South than
in the West.
Public Safety: Predicted Effects of Density (Per Capita)
Per Square Mile
Predicted Spending Relative to Base
Predicted Spending in
Source: Adapted from Ladd 1992, p. 291
Although the results are non-linear, Ladd's findings
are not hard to interpret. Those who feel that increasing population
density will decrease costs to local governments are correct, but
at very low levels of population density. "The increasing per capita
spending as the density of counties rises above 250 people per square mile
provides important evidence to counter the view, which emerges from engineering
and planning studies, that higher density reduces public sector costs (pp.
291-292)." For most situations, more population density equals MORE
per capita costs to government.
Since population growth does result in higher costs,
the public issue arises as to whether newcomers should be forced to pay
extra to live in a community through impact fees. This is the normative
situation in the United States. Young families buying a new house
are thus forced to pay school, road and density impact fees. Ladd
asks the interesting question if this is just. The article concludes
with the statement about new development:
Of course, the normative question of whether it (growth) should
be asked to pay its way in order to hold harmless established residents
is a different question, and one that is beyond the scope of this paper.
One should note, however, that to the extent that the fiscal burden on
established residents arises because of the higher overall density in the
county, it is hard to make an economic argument for high financing burdens
on new residents alone; after all, the established residents are
as much a cause of the higher density as are the new residents (p. 293).
More broadly stated, the issues raised by Ladd are important
from a social justice point of view. Should new families buying their
first house pay, for example, a school impact fee? Is this not just
a quiet way of charging young families tuition for public education, a
fee not charged to existing residents?
The 2000 census shows that more and more people in
the United States are moving into a few areas of increased population concentrations
as the rural economy continues its historic decline. Population concentration,
not sprawl, will continue to be a major social factor in the coming years.
And as the one industrial nation with substantial population growth, it
is quite clear that increased costs of public services which happen with
growth and increased population density will continue to be widely discussed.
Downing, P.B. and Gustley, R. D. (1977). "The Public Service
Costs of Alternative Development Patterns: A Review of the Evidence."
In P. B. Downing (Ed.) Local Services Pricing Policies and Their Effect
on Urban Spatial Structures. Vancover: University of British
Real Estate Research Corporation (1974). The Costs of Sprawl:
Environmental and Economic costs of Alternative Residential Development
Patterns at the Urban Fringe.. Washington, DC: USGPO.
Wirth, Louis  1969. "Urbanism as a Way of Life." In Classic
Essays on the Culture of Cities, ed. Richard Sennett. New York: Appleton-Centry-Crofts:
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