Malcolm Gladwell has a good article on disproportionality in the New Yorker Millon Dollar Murray: Why problems like homelessness may be easier to solve than to manage. His article focuses on homelessness and air pollution – on how most of the cost of homelessness and comes from a tiny part of the homeless population – and how most air pollution comes from a tiny part of the car population.
Disproportionality is fairly general in many forms of environmental impact. For example, in the Lake Mendota watershed in Wisconsin, most of the phosphorus pollution comes from only a few of the farms in the watershed. However, ecological disproportionality is complicated by the fact that the vulnerability of different sites to human impact also varies – which compounds the disproportionality.
In a recent paper Disproportionality as a Framework for Linking Social and Biophysical Systems (Society and Natural Resources 2006 19:153-173) Pete Nowak, Sarah Bowen, and Perry Cabot write
Early social science was influenced by the work of Adolphe Quetelet, who promoted the idea that the average in a normal distribution represented the ‘‘essence’’ of a social system whereas variance or outliers were viewed as ‘‘accidents’’ in the study of social processes (Kruger et al. 1990). Charles Darwin, on the other hand, viewed variance, or the outlier, as central to understanding evolutionary biological processes. In this article, we have argued that giving more attention to variance across multiple scales can serve as a conceptual bridge between the social and biophysical sciences. Disproportionality is a concept that can bridge disciplines by focusing on the salient interactions between humans and their environments at different spatial and temporal scales.
Nowak et al use the example of farming practices and phosphorus runoff to explore how disproportionality in social and ecological systems intersects. They use the figure below to illustrate how the impact of a behaviour is shaped by place and timing.
Figure (from Nowak’s paper) The combination of typical conservation behavior, exhbiting a skewed normal or log-normal probability distribution, and typical environmental conditions, also exhbiting a skewed normal or log-normal probability distribution of the probability of environmental risk, combines to produce a situation in which a small proportion of inappropriate social behaviors within a particularly vulnerable setting can have a disproportionately large impact on overall environmental quality of an ecological system.
Nowak et al write:
Our conception of disproportionality emphasizes that human contributions to environmental degradation are not normally or randomly distributed, but arrayed in a way that may be strongly skewed and determined by the specific biophysical setting where it takes place. This view of disproportionality is a derivative of Robinson’s (1950) ecological fallacy in that the environmental performance of a unit of social organization does not imply that all individuals within that organization perform in a similar fashion. Because logging, mining, agriculture, or suburban development degrades the environment, for instance, this does not mean that all loggers, miners, farmers, or developers are equal contributors to degradation. The classic scientific caveat, ‘‘It depends,’’ conditions the impact of behavior based on the setting of that behavior. Furthermore, the log-normal world suggested by Limpert et al. (2001) implies that a very small minority within a social group may cause significantly greater environmental degradation, and possibly more than the combined impact of the remaining group. This disproportionate outcome occurs, not because the behavior of the minority is especially egregious or deviant, but because their actions are inappropriate behaviors taking place in biophysically vulnerable settings or times.
Employing this concept of disproportionality suggests that environmental sociologists need to account for both the distribution of behaviors within social organizational boundaries and, equally important, the distribution of the resiliency of the biophysical settings of those behaviors. Acknowledging that disproportionality may drive the improvements or degradation in an ecological system requires social scientists to explicitly account for within-group variation of social actors. Depending on the biophysical setting, only a few cases may have a disproportionate impact on the overall ecological system being studied. The potential for this form of disproportionality implies that the environmental meaning placed on a social behavior requires accounting for where and when it occurs in a biophysical setting. We emphasize that the social interpretation placed on any behavior by environmental social scientists, and any subsequent analysis of the ecological impacts of this behavioral pattern, must take into account where and when the behaviors occur in an ecological setting (Abbott 1999). The interaction between the characteristics of the behavior and the biophysical setting where the behavior occurs should determine the meaning placed on that behavior. For example, the all-too-common term of ‘‘bad actor’’ is only partially correct; both the ‘‘acting’’ and the ‘‘stage’’ for that action need to be used in forming such ill-advised value judgments. In our examination of the Pheasant Branch watershed, we found that the concept of disproportionality offered an approach to addressing the question of why significant changes in the social system did not induce parallel changes in the biophysical system.
Gladwell’s New Yorker article provides other clear examples of social disproportionality. He focuses on homelessness and how policies that try to grapple with its disproportionality face ethical issues:
… fifteen years ago, a young Boston College graduate student named Dennis Culhane lived in a shelter in Philadelphia for seven weeks as part of the research for his dissertation. A few months later he went back, and was surprised to discover that he couldn’t find any of the people he had recently spent so much time with. “It made me realize that most of these people were getting on with their own lives,” he said.
Culhane then put together a database—the first of its kind—to track who was coming in and out of the shelter system. What he discovered profoundly changed the way homelessness is understood. Homelessness doesn’t have a normal distribution, it turned out. It has a power-law distribution. “We found that eighty per cent of the homeless were in and out really quickly,” he said. “In Philadelphia, the most common length of time that someone is homeless is one day. And the second most common length is two days. And they never come back. Anyone who ever has to stay in a shelter involuntarily knows that all you think about is how to make sure you never come back.”
The next ten per cent were what Culhane calls episodic users. They would come for three weeks at a time, and return periodically, particularly in the winter. They were quite young, and they were often heavy drug users. It was the last ten per cent—the group at the farthest edge of the curve—that interested Culhane the most. They were the chronically homeless, who lived in the shelters, sometimes for years at a time. They were older. Many were mentally ill or physically disabled, and when we think about homelessness as a social problem—the people sleeping on the sidewalk, aggressively panhandling, lying drunk in doorways, huddled on subway grates and under bridges—it’s this group that we have in mind. In the early nineteen-nineties, Culhane’s database suggested that New York City had a quarter of a million people who were homeless at some point in the previous half decade —which was a surprisingly high number. But only about twenty-five hundred were chronically homeless.
It turns out, furthermore, that this group costs the health-care and social-services systems far more than anyone had ever anticipated. Culhane estimates that in New York at least sixty-two million dollars was being spent annually to shelter just those twenty-five hundred hard-core homeless. “It costs twenty-four thousand dollars a year for one of these shelter beds,” Culhane said. “We’re talking about a cot eighteen inches away from the next cot.” Boston Health Care for the Homeless Program, a leading service group for the homeless in Boston, recently tracked the medical expenses of a hundred and nineteen chronically homeless people. In the course of five years, thirty-three people died and seven more were sent to nursing homes, and the group still accounted for 18,834 emergency-room visits—at a minimum cost of a thousand dollars a visit.
…
The current philosophy of welfare holds that government assistance should be temporary and conditional, to avoid creating dependency. But someone who blows .49 on a Breathalyzer and has cirrhosis of the liver at the age of twenty-seven doesn’t respond to incentives and sanctions in the usual way. “The most complicated people to work with are those who have been homeless for so long that going back to the streets just isn’t scary to them,” Post said. “The summer comes along and they say, ‘I don’t need to follow your rules.’ ” Power-law homelessness policy has to do the opposite of normal-distribution social policy. It should create dependency: you want people who have been outside the system to come inside and rebuild their lives under the supervision of those ten caseworkers in the basement of the Y.M.C.A.
That is what is so perplexing about power-law homeless policy. From an economic perspective the approach makes perfect sense. But from a moral perspective it doesn’t seem fair. Thousands of people in the Denver area no doubt live day to day, work two or three jobs, and are eminently deserving of a helping hand—and no one offers them the key to a new apartment. Yet that’s just what the guy screaming obscenities and swigging Dr. Tich gets. When the welfare mom’s time on public assistance runs out, we cut her off. Yet when the homeless man trashes his apartment we give him another. Social benefits are supposed to have some kind of moral justification. We give them to widows and disabled veterans and poor mothers with small children. Giving the homeless guy passed out on the sidewalk an apartment has a different rationale. It’s simply about efficiency.
We also believe that the distribution of social benefits should not be arbitrary. We don’t give only to some poor mothers, or to a random handful of disabled veterans. We give to everyone who meets a formal criterion, and the moral credibility of government assistance derives, in part, from this universality. But the Denver homelessness program doesn’t help every chronically homeless person in Denver. There is a waiting list of six hundred for the supportive-housing program; it will be years before all those people get apartments, and some may never get one. There isn’t enough money to go around, and to try to help everyone a little bit—to observe the principle of universality—isn’t as cost-effective as helping a few people a lot. Being fair, in this case, means providing shelters and soup kitchens, and shelters and soup kitchens don’t solve the problem of homelessness. Our usual moral intuitions are little use, then, when it comes to a few hard cases. Power-law problems leave us with an unpleasant choice. We can be true to our principles or we can fix the problem. We cannot do both.
The entire article Millon Dollar Murray: Why problems like homelessness may be easier to solve than to manage is interesting.