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Demography Handout


									                                             Demography Handout
Demography is the study of human populations. Demographers study population size, population distribution and
population change. In this course, we will use simple demographic techniques to analyze regions. This handout will
outline some basic demographic principles, as well as define many of the terms used in the statistical datasheets
provided for each region covered in this course.

It is wise to be skeptical of statistics for a number of reasons. First, keeping accurate statistics is both time
consuming and expensive. Even in wealthy countries, like the United States, where a lot of time and money are
devoted to the endeavor, census data are not perfectly accurate. In countries with fewer resources to devote to the
effort, the data may be even more questionable. Second, countries may want to exaggerate some statistics, such as
literacy, or minimize others, such as infant mortality, to make themselves look good. .Third, not all countries define
statistics the same way. For instance, each country has its own definition for percent urban. Rwanda and Burundi,
for instance, have very similar settlement patterns. Rwanda claims that 17% urban population while Burundi claims
that only 9% of its population is urban. Some countries do not count in their infant mortality rates babies who die
within the first 24 hours or children who are very premature.

So, while you keep a healthy dose of skepticism, remember that these statistics are the best we have. Although we
cannot take them completely at face value, they can provide us with a good idea of conditions within a country or a
region. Throughout the semester, we will use these statistics to try to do just that.

Population Size

The earth has a population of about 6.6 billion people. The most populous country is China, with 1.3 billion people.
The least populous country is Vatican City, with a population of about 1000 people. Knowing the total population
does not provide a lot of meaningful information about a country, but it does provide a couple of clues. For
instance, a huge country usually has more of an impact on the world. In spite of the Vatican City’s importance
within the Roman Catholic Church, changes in the behavior of the people of China have a much greater impact on
the world than changes of behavior in Vatican City. The United States is not the richest country in the world in spite
of what many of us believe; the average income in Luxembourg is about 50% higher than the average income in the
United States. However, with about 300 million people, the United States economy is the biggest in the world and
events in the U.S. economy have a much greater impact on the world economy than events in Luxembourg.

Many of us are concerned about the overpopulation. We are worried that the earth doesn’t have enough resources to
sustain everyone. But for individual countries, larger populations can provide a solid base for economic growth by
providing both a market for goods and a reliable supply of labor.

Population Density

While geographers are interested in total population size, they are also interested in population densities. There are
two types of population density: arithmetic population density and physiological density. Arithmetic density is the
simpler of the two measures. It considers only the number of people and the total amount of land. Usually when
people refer to “population density,” they mean arithmetic density. Physiological population density considers the
amount of land that can be farmed rather than the total land.

                      Arithmetic Population Density = Total Population / Total Land Area
                   Physiological Population Density = Total Population / Area of Arable Land

The average arithmetic population density of the earth is 127 people per square mile.
                     Earth’s arithmetic density = 6.6 billion people / 52 million square miles
                                           = 127 people / square mile
About 10% of the earth’s land surface is arable. The average arithmetic population density is about 1270 people per
arable square mile. There are two ways to calculate this. The first way involves calculating the amount of arable
land and dividing that into the total population.
Method 1:
                                 Area of Arable Land = Total Land * Percent Arable
            Area of Arable Land = 52 million square miles * 10% arable = 5.2 million arable square miles
                Physiological Population Density = 6.6 billion people/ 5.2 million arable square miles
                                          = 1270 people / arable square mile

Method 2:
The second method is simpler. Simply divide the arithmetic population density by the percentage of arable land.
                 Physiological Population Density = Arithmetic Population Density / Percent Arable
    Physiological Population Density = 127 people / square mile/ 10% arable = 1270 people / arable square mile
Note: Physiological population density will be higher that arithmetic population density because the arable land
area is always less than the total land area.
More Examples
Let’s look at Western Sahara. It has a simple population density of 4 people per square mile. According to the CIA
Factbook, it has NO arable land! Because you can’t divide by zero, you can’t calculate an exact figure, but you
know that the physiological population density is VERY high!
Let’s look at a country that does have calculable figures: Kenya, a country in East Africa that has been in the news
lately, has a population of roughly 35 million people. It has a total land area of 225,000 square miles. About 8% of
its total land area is farmable.
Method 1:
    Liberia’s Arithmetic Population Density = 35,000,000 people / 225,000 sq. mi. = 156 people per square mile
                                 Total Farmable Land = Total Land * Percent Arable
                      Liberia’s Total Farmable Land = 225,000 sq. mi. * 8% = 18,000 sq. mi.
                  Liberia’s Physiological Population Density = 35,000,000 people / 18,000 sq. mi.
                                        = 1944 people per arable square mile.
Method 2:
                   Liberia’s Physiological Population Density = 156 people per square mile / 8%
                                        = 1944 people per arable square mile
Explaining Arithmetic Population Density
Arithmetic population densities vary a lot across the world. Monaco has the highest population density of any
sovereign country, with 44,000 people per square mile. Western Sahara, dominated by desert, has the lowest
population density of any sovereign country, with only 4 people per square mile.
What accounts for the differences in population densities? Population density is a complex phenomenon. The most
important explanation for high population density is accessibility. Accessibility refers to how easy it is to get to or
travel within an area. Accessibility is greatly affected by a country’s landforms and climate and whether it is
landlocked. Even with modern aircraft, some places are much more accessible than others. Places that are highly
accessible tend to have higher arithmetic population densities than areas that are not.
In The Geography of Wealth and Poverty, the authors measure accessibility with a single measure – whether a
country is landlocked. This measure works well as a simple way to promote the authors’ argument. It is more
difficult to create a numerical value that measures a country’s internal accessibility. If you could, that measure
would probably make the authors’ argument even stronger. Take the island of Borneo; located in Southeast Asia, it
is one of the larger Indonesian islands. It is easy to get to the coast of Borneo by boat, but the interior is dominated
by rugged, jungle-covered mountains, which severely limit internal accessibility.
Arability (percent arable) specifically refers to the percent of land that can be farmed. This is a function both
climate and of rock type, which is linked to landforms. Areas where a high proportion of the land is arable can feed
more people and are therefore able to support larger populations. While arability is important, it is a less important
factor than accessibility in explaining arithmetic population density.
The presence of climate-related diseases also lowers population density. Low-latitude areas tend to have more
climate-related diseases. In The Geography of Wealth and Poverty, the authors focus on malaria. Endemic to warm,
humid climates, malaria weakens and kills population, sapping economic strength. Other diseases, like sleeping
sickness, dengue fever, schistosomiasis, and leprosy also weaken populations and economies.
Students will often say that a country is densely populated because it is small or sparsely populated because it is big,
but there is little relationship between the size of a country and its population density. You can make that argument
if you look at the very largest and very smallest countries, but in between there is not much of a relationship
between country size and arithmetic population density.
It is hard to tell from population density alone whether a country is “too” crowded. Overpopulation is a function of
a country’s being able to feed itself. To get some gauge of a country’s ability to feed its people, researchers often
use physiological population density. It is not a perfect statistic because it does not take into account differences in
how productive the arable land is or whether the population needs to raise the food that it eats. Of the countries for
which statisitics are available, Australia has the lowest physiological population. Australia is a large country with a
very small population. It is the 18th richest country in the world. On the other hand, tiny, landlocked Bhutan,
located north of India in South Asia, has the second lowest physiological population density. It is the 28th poorest
country in the world.
Population Change

Natural Increase
Throughout the last few centuries, the world’s population has steadily grown. In 2007, the world’s population will
increase by approximately 80 million people – that’s about the size of the population of Egypt. The world’s
population changes because of natural increase – the difference between births and deaths.
Demographers record birth and death rates per 1000 people in the population. These are called crude birth (CBR)
and crude death rates (CDR).
According to the 2006 Population Data Sheet, the world crude birth rate is 21 and the crude death rate is 9. The
total population of the world is 6.6 BILLION. To calculate the total number of births and deaths in the world,
                                    Number of Births / 6,600,000,000 = 21/1000
                                   Number of Births = (6,600,000,000 * 21) / 1000
                                           Number of Births = 138,600,000
                                     Number of Deaths / 6,600,000,000 = 9/1000
                                   Number of Deaths = (6,600,000,000 * 9) / 1000
                                           Number of Deaths = 59,400,000

So in 2007, there should be about 139 million births around the globe – about the same size as the population of
Japan! During the same period, there should be about 59 million deaths – about the same size as the population of
Italy!. The population should increase by 80 million!
Rate of Natural Increase (RNI)
Typically, demographers don’t look at raw numbers, but calculate the rate of natural increase. This is the percentage
that a population grows (or shrinks) each year. To calculate,
                        Rate of Natural Increase = Crude Birth Rate – Crude Death Rate
To calculate the rate of natural increase of the world, we have
                                                RNI = (21/1000) – (9/1000)
                                                     RNI = 12/1000
                                                      RNI = 1.2/100
                                                       RNI = 1.2%
The world is growing at a rate of 1.2% per year.
Doubling Time
Doubling time is the number of years it takes for a population to double its size through natural increase alone. To
calculate the doubling time, you divide 72 by the rate of natural increase. (72 is a constant. You just have to
memorize it. If you want to know where the 72 comes from, check out the following website:
                                           DOUBLING TIME = 72 / RNI
For the world, the doubling time is
                                           DOUBLING TIME = 72 / 1.2
                                         DOUBLING TIME = 60 YEARS
So, if it continues to grow at the same rate, the world will have a population of 12.4 BILLION people by 2065!
That’s within your lifetime!
Demographic Transition
It is unlikely that the world RNI would remain the same over
the next 60 years. In fact, the rate of population growth has
been slowing for at least a decade. Based on statistics of
British birth and death rates, demographers have come up with
what is known as the Demographic Transition Model.
Stage 1: Birth rates are high and death rates are high. They
cancel each other out, leading to slow growth.
Stage 2: Birth rates are high, but death rates are falling. The
RNI increases during this stage so that they are fastest at the
end of Stage 2.
Stage 3: Death rates level off and birth rates begin to decline.
The RNI is high at the beginning of Stage 3, but it falls
throughout the period.
Stage 4: Birth rates and death rates are low.
How can you tell which stage a country is in? If the RNI is negative, check the birth rate. Is it low or high? Niger
has the highest CBR, at 55. Latvia has the lowest CBR, at 8. The average for the world is 21, as we discussed
above. If the CBR is high, then the country is probably in Stage 1. If it is low, then the country is in Stage 4.
What if the RNI is moderate – How do you tell if the country is in Stage 2 or Stage 4? The easiest way is to plot the
birth and death rates. Look at the chart. High crude birth and crude death rates fall between 35 to 40. Low crude
birth and death rates drop to about 10. East Timor and Saudi Arabia each have very high rates of natural increase –
2.7%. (What is their doubling time?) They are not in the same stage of the demographic transition, however. East
Timor, with a crude birth rate of 42 and a crude death rate of 15, is in late II. This means that East Timor will grow
at faster rates in the near future. Saudi Arabia has much lower birth and death rates: Its crude death rate is 30 and
its crude death rate is 3. Therefore, Saudi Arabia is in the middle of Stage III. Its rate of natural increase is slowing.
For more information about the demographic transition model, see
Explaining Birth Rates
Birth rates vary widely across the globe. Currently, Niger, in West Africa, has the highest crude birth rates – 55.
Germany has the lowest at 8. What accounts for the vast differences in birth rates? It may seem logical that birth
rates are higher where women have less access to birth control. I don’t think access to birth control is an important
explanatory factor. The underlying assumption in this claim is that the women who are having babies don’t want
them. I would argue that women who don’t want more babies can find ways to avoid them. They can nurse their
children longer, practice abstinence, have abortions, or practice infanticide. In countries that industrialized early,
birth rates declined long before modern birth control techniques became available. Therefore, I think it is safe to
argue that in countries where birth rates are high, children are desired and countries where birth rates are low,
children are not desired. Three factors do help explain birth rates: the percentage of farmers, pronatalist religions,
and the presence of ethnic conflict.
Percentage of Farmers
Sitting in the United States in 2007, it is hard to imagine why anyone would want a large family. Children are
expensive. Typically, they are a drain on family resources. From the time they are born until their early twenties,
children can cost their parents thousands of dollars each year in education, housing, clothing, food, insurance,
entertainment and a myriad other costs. In the United States, it is not typical for children to contribute financially to
a family’s well being even when parents get older. Therefore, in countries like the United States where children are
an economic burden, families tend to be very small.
In countries where farmers constitute a large proportion of the population, the situation is very different. Children
are not economic burdens; they are economic assets. Children can go to work for the family at a very young age,
tending chickens, weeding vegetable gardens, and collecting fuel. Further, when there are lots of farmers, it is
unlikely they have a retirement plan. Children are expected to care for their parents in their old age. If infant
mortality and childhood death rates are high, parents will want bigger families to insure that some will survive to
care for their parents.
This issue often gets confused with poverty. It is generally true that poorer countries tend to have higher birth rates
than richer countries. However, poor countries with a small proportion of farmers do not have high birth rates.
Russia is an example. The per capita income of Russia is below the world average, but almost three quarters of the
population lives in urban areas. In spite of Russia’s relative poverty, Russia’s crude birth rate is only 10 – less than
half the world average.
Pronatalist Religions
Religion can have an important role in the number of births. Many studies have found that if you control for
education, occupation, and percent urban, the role of religion decreases in importance. For instance, in Catholic
Italy, where most people are highly educated urban dwellers, the crude birth rate is only 10. On the other hand, in
East Timor, another Catholic country, where most people are poorly educated subsistence farmers, the crude birth
rate is 42.
In the United States, however, Utah, which is predominantly Mormon, has the highest birth rate among the states.
In spite of the fact that its population is 88% urban, the CBR in Utah is 21. In neighboring Arizona, which is also
88% urban, the CBR is only 16. Clearly, the religion has an impact.
Although it is true that the birth rate among Muslims is declining, Islamic areas have an average RNI of 1.9% --
much higher than the world average. (Yes, it is only 0.7% difference, but consider this: the world has a doubling
time of 60 years, while Islamic areas have a doubling time of 38 years. A tiny difference in the RNI can have a huge
impact on doubling time. Also, that 0.7% represents more than 50% of the world’s average RNI.)
The November, 2006, issue of The Nation had an article about Quiverfull, a fundamentalist Christian organization
that promotes large families. Each child is an arrow in the quiver in the struggle against the forces of evil.
According to The Nation,
    Quiverfull parents try to have upwards of six children. They home-school their families, attend
    fundamentalist churches and follow biblical guidelines of male headship--"Father knows best"--and female
    submissiveness. They refuse any attempt to regulate pregnancy. Quiverfull began with the publication of
    Rick and Jan Hess's 1989 book, A Full Quiver: Family Planning and the Lordship of Christ, which argues
    that God, as the "Great Physician" and sole "Birth Controller," opens and closes the womb on a case-by-
    case basis. Women's attempts to control their own bodies--the Lord's temple--are a seizure of divine power.
Ethnic Conflict and the Vulnerable Minority
Minority groups, particularly those who feel threatened by outsiders, may also have higher birth rates. This is
painfully evident in war-torn areas. In the Palestinian Territories, where poverty and violence are commonplace, the
CBR is 37. In Catholic East Timor, which fought for independence from Muslim Indonesia for over two decades,
the CBR is 41. War-torn Afghanistan also has a very high birth rate. For many of us, this makes no sense. Why
would people want to bring children into a world that is so dangerous and so unstable? There may be a couple of
reasons. One, in such insecure times, parents may want to insure that some of their children live to be adults who
can help support them. Another may be that people want to make sure their minority group survives and having lots
of children can help assure that.
Explaining Death Rates
The average death rate around the globe is 9, but there is a lot of variation. The highest death rate, 28, is found in
Swaziland, a small country in Southern Africa. In the United Arab Emirates, however, only 1 out of every 1000
people dies each year. Three important factors contribute to death rates: the wealth of a country, the age structure
of a country, and the prevalence of infectious diseases.
Wealth and Poverty
In wealthy countries, people have better access to clean water, nutritious food and health care than people in poor
countries. The average life expectancy in more developed countries is 77 years; in less developed countries it is
only 64 years. In more developed countries, only six out of every 1000 babies born dies before their first birthday.
In less developed countries, ten times as many babies die.
Age Structure
The death rate for seniors is much higher than that for young people. In the United States, there are 50 deaths per
year for every 1000 people over 65. Among 1000 young people aged 15 to 24, there will be less than one death a
year. This is true for much of the world. Older populations will elevate the raise death rates and younger
populations will lower death rates. In Monaco, 22% of the population is at least 65 years old. In spite of being a
more developed country, Monaco’s crude death rate is 16 – almost twice as high as the world average. In the United
Arab Emirates, only 1% of the population is 65 years old or more. There, the crude death rate is only 1.
Prevalence of Infectious Diseases
In low-latitude areas, insect-borne diseases are an on-going problem, weakening populations, lowering life
expectancy, and raising the death rate. Poverty, particularly rural poverty, only makes the problem worse. Of the 20
countries with the highest death rates, 18 are located in the low latitudes. The rise of AIDS complicates the picture.
AIDS rates are particularly high in Africa. The five countries with the highest crude death rates four are countries
where more than 20% of the young adult population is infected with HIV.
Migration is another factor that contributes to population change of individual places.
                Population Change = Natural Increase or Decrease + Immigration - Emigration
Migration is simply the movement of people from one place to another. It may be seasonal, long-term, or
permanent. Seasonal migration is generally due to the seasonal availability of jobs. Farm workers, for instance, are
typically hired for planting or harvesting, and then let go in between. Some migrations may be long term, with the
migrant moving for extended periods, but with every intention of returning to their homes. They often leave their
families behind and almost always maintain close contact with family and friends back home. Finally, some
migration is permanent. Migration may be local, regional, national or international. Migration may be legal or
illegal. Migration may be voluntary or forced.
People move from one place to another for a complex set of reasons. These reasons can be divided into push factors
and pull factors. Push factors are those that push a person away from their place of origin. Pull factors are those
that pull a person to a specific place.
Net migration refers to the difference between immigration (in-migration) and emigration (out-migration). Some
countries, like the United States, have a large positive net migration. Other countries, like Russia, are experiencing
large negative net migration. The general flow of migration is from poor countries to rich countries or from relative
chaos to relative calm.
Other Demographic Variables
Age Structure and Life Expectancy
Demographers often look at the age structure of a population, sometimes simplifying it by looking at the percent less
than age 15 and the percent 65 years old or more. Approximately 30% of the world’s population is under 15 years
old. 7% is 65 and older. These ages are significant because between people between 15 and 65 are classified by
demographers and economists as the productive population – those whose work supports the young and the old. The
young and the old are classified as the dependent population. In developing countries where birth rates are high,
there is likely to be a high proportion of young dependents. This is a bit misleading, however, since these poor
countries will often be agricultural countries and young people are not dependent as long as they are in developed
countries. In more developed countries, where birth rates are low, there is likely to be a high proportion of old
dependents. As life expectancy increases, dependency can stretch our many years. In Japan, for instance, female
life expectancy is 86 years. That means the average female can expect a retirement of more than 20 years. Older
dependents are also more expensive than younger dependents, particularly with respect to health care.
As you have already read, age structure affects death rates. It also affects birth rates. Young populations tend to
have more children than old ones. If there is a large population under age 15, it is likely that the population will
continue to grow over the next decade or more as young children reach child-bearing age. Young populations can
indicate the potential for economic growth because they have a group of people who will soon move into their
productive years.
Linked to age structure is life expectancy, which is the number of years a newborn baby can expect to live. It is
divided into statistics for males and for females. The average male life expectancy for the world is 65. The average
female life expectancy is 69. A hundred years ago, males outlived females because so many women died during
childbirth. In most countries of the world, females can expect to outlive men. The more developed a country, the
greater the gap between male and female life expectancy. In the “more developed world,” male life expectancy is
72 and female life expectancy is 80. In the “less developed world,” male life expectancy is 61 and female life
expectancy is 64.
In countries of Central and Southern Africa where high rates of HIV/AIDS are prevalent, life expectancy has fallen
to less than 40 years. This has a huge impact beyond life expectancy. A society where people usually don’t live
beyond 40 cannot expect to train doctors, scientists, engineers, or teachers. A person’s productive years are cut in
half. Families are impoverished and the entire economy is weakened. When medical costs are added, the situation
is even more desperate.
Infant Mortality
The infant mortality rate is defined as the number of children who die before their first birthday for every 1000 live
births. Historically, the primary cause of infant mortality worldwide was diarrhea. Currently, however, due to the
widening use of hydration therapies, diarrhea has dropped to the number two cause of infant deaths and pneumonia
is now the leading cause.
The global infant mortality rate is 52. That means 52 out of every 1000 babies die before their first birthday –
slightly more than 2%. Infant mortality rate, like other statistics, varies widely from region to region. The lowest is
Singapore, with an IMR of 2.1. Some researchers dispute these findings, claiming that Singapore omits premature
births and babies who die within the first day of birth, but it is likely that the IMR in Singapore is still quite low.
The highest IMRs are found in Afghanistan and Sierra Leone. Both countries are poor, and both countries have
been plagued by civil unrest.
In general, wealthier, more urban, and more stable societies have lower infant mortality rates than poorer, more rural
and politically unstable societies.
Percent Urban / Percent Farmers
This refers to the percent of the population that lives in urban areas. What constitutes an urban area is determined
by the country itself and changes from country to country. How an individual country defines urban also changes
over time.
In spite of its deficiencies, the data for percent urban are available for almost every country in the world. Percent
urban is an acceptable substitute for knowing what percent of the population are farmers since farmers usually do
not live in urban areas. If an area has a high percent urban, it likely has a very low percentage of farmers. Farming
is likely modern commercial farming. If an area has a low percent urban, it is likely that there will be a high
percentage of farmers. Where the percentage of farmers is high, most farmers are usually subsistence farmers who
farm primarily for personal consumption rather than for sale. Therefore, the percent urban is a fair predictor of
national wealth or poverty: urban countries tend to be wealthier than rural countries.
Percent of Population with Access to Improved Sanitation
This statistic shows what percentage of the urban population and what percentage of the rural population has access
to improved sanitation. Typically this means modern plumbing that provides fresh water and carries away waste
water. Improved sanitation is critically linked to health. In the more developed world, both urban and rural
populations are listed as having 100% access to improved sanitation. The 100% should not be taken literally.
Rather, it should be taken to mean just about 100%. In the less developed world, access to improved sanitation
declines, particularly in rural areas.
Because of less access to improved sanitation, areas with large rural populations tend to have higher infant mortality
and lower life expectancy than areas that are more urban. Take the cases of India and Cuba, both of which have
average per capita incomes of about $3500. In India, more than 70% of the population lives in rural areas compared
less than 24% of the population of Cuba. India has an IMR ten times higher than Cuba’s (58 vs. 5.8); India’s life
expectancy is more than ten years shorter than that of Cuba. Of course, percent urban only partially explains Cuba’s
superior health statistics. Despite Cuba’s poverty, rural populations have greater access to improved sanitation than
India’s rural population. High access to improved sanitation in a poor country is generally a good indicator of
socialized medicine.

This handout discusses most of the variables on the data sheets provided for each region. Through this discussion, I
hope you have understood that no single statistic can tell you a lot about a country, but a set of statistics can give
you a good idea about a country or a region. Throughout the course, we will use these statistics to analyze regions.
For extra credit, you will use these and other statistics to analyze a country.

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