Modeling the Effect of Income Segregation on Communicable Disease Transmission

• Author: Anh Pham
• Published date: 01 September 2019
• Date: 01 September 2019
• DOI: http://doi.org/10.1002/wmh3.311

288

doi: 10.1002/wmh3.311

© 2019 Policy Studies Organization

Modeling the Effect of Income Segregation on

Communicable Disease Transmission

Anh Pham

Income segregation has been on the rise in developing countries, where many communicable diseases

are still prevalent. This study investigates how income segregation affects communicable disease

transmission through the development of a novel model that includes income segregation and in-

dividuals’health‐seeking behavior. The general model proposed here assumes that health of an in-

dividual is affected by (i)the health‐seeking behavior of individuals (e.g., going to the hospital, taking

medicine);(ii)the communal health stock; and (iii)exposure to the communal health stock. The

communal health stock is comprised of the amenities that make people healthier in a given community

(e.g., the number of health‐care facilities). Income segregation is defined here as a combination of

income inequality and residential segregation, which exists when some people have higher exposure to

the communal health stock than other people. In this model, income segregation exists when poor

people disproportionately live in neighborhoods with lower exposure to the communal health stock

than rich people. A decrease in income segregation means the income of the poor increases along with

their exposure to the communal health stock. The general model applied here predicts that an increase

in the poor’s income will increase their health by enabling them to afford more health‐seeking behavior

and finds that higher exposure to the communal health stock directly increases the health of the poor.

Higher exposure to the communal health stock, however, is found to decrease the poor’s health‐seeking

behavior, which reduces their health. The general model finds, therefore, that a decrease in income

segregation will have an ambiguous effect on the health of individuals and the overall community.

Probing further, the analysis replaces the general model with a more specific model, which predicts

that overall, a decrease in income segregation increases individual health. Furthermore, in the more

specific model, it is possible that the poor get stuck in a low‐health equilibrium while the rich stay in a

high‐health equilibrium.

KEY WORDS: income segregation, communicable diseases, healthy behavior

Introduction

Income segregation, in which gated communities separate the rich and the

poor, has been rising in developing countries, where communicable diseases are

still prevalent.

1,2

Avoiding disease outbreak is one of the most important goals of

public health. This paper develops a novel theoretical model that examines how

income segregation affects communicable disease transmission. Understanding the

link between the two can inform the thinking of public health officials in the

development of policy and allocation of resources needed to mitigate the trans-

mission of communicable diseases and thereby protect public health.

The model proposed here mostly applies to dense urban areas in developing

countries, where public health systems are weak and spatial health externalities are

prevalent because of communicable diseases. In the proposed model, an individual

maximizes his or her utility (happiness)by choosing between health and other

consumptions. A person’s health is affected by three inputs: (i)health‐seeking be-

havior, (ii)communal health stock,

2

and (iii)exposure to the communal health

stock. Health‐seeking behaviors are any behaviors that individuals take to improve

their health. Some examples of health‐seeking behaviors are going to the hospital,

taking medicine, and getting vaccinated. Communal health stock is comprised of

things in the community that are good for an individual’s health, for example, the

number of hospitals or health‐care facilities, the availability of clean water, and the

number of healthy residents in the community. The communal health stock is

modeled as a weighted average of individuals’health. It is assumed that higher

exposure to the communal health stock means better access to things in the com-

munity that are good for an individual’s health (such as good health‐care services

and clean water)and less exposure to things in the community that are bad for an

individual’s health (such as pollutants). Thus, it is assumed that higher exposure to

communal health makes individuals healthier. It is also assumed that a person’s

health‐seeking behavior is more effective in increasing their health when the

communal health stock is low (e.g., fewer healthy residents in the community or

fewer health‐care facilities). Furthermore, it is assumed that if a person is more

exposed to the communal health stock, the effect of health‐seeking behavior on this

person’s health is weaker. Though these assumptions may not always be true, they

are presumed for the purposes of this analysis. Examples of situations when these

assumptions hold are offered in the “Assumptions”section, while the examples of

situations when these assumptions may not hold are in the “Model Limitations”

section, with some discussion of how this affects the model’s results.

In a perfectly equal and unsegregated world, everyone would have the same

exposure to the communal health stock and the same income. Income inequality

exists, quite simply, when the rich have a higher income than the poor. Residential

segregation exists when some people in a community have higher exposure to the

communal health stock and other people have lower exposure.

3

Income segregation

exists when both income inequality and residential segregation exist in a way that

results in poor people living in a community with less exposure to the communal

health stock (e.g., worse access to health care)and rich people living in a com-

munity with high exposure to the communal health stock (e.g., better access to

health care). Thus, by this definition, a decrease in income segregation raises the

income and exposure of the poor while reducing them for the rich.

The general model proposed here finds that income segregation has an am-

biguous effect on an individual’s health and thus the communal health stock, de-

pending on whether the effect of the income and exposure to the communal health

stock are stronger or an individual’s health‐seeking behavior effect is stronger. A

decrease in income segregation means that the poor have more money and higher

Pham: Effect of Income Segregation 289