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, 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 example, each country has its own definition for percent urban. Rwanda and Burundi,
neighboring countries in east central Africa, have very similar settlement patterns, but in Burundi only the capital
city is classified as urban while Rwanda defines a broader range of cities and towns as urban. Consequently,
Burundi claims that only 10% of its population is urban while in Rwanda the percent urban is 17%. Another
example is that some countries do not count in their infant mortality rates babies who die within the first 24 hours or
children who are very premature while other countries count all children born alive in their infant mortality rates.
So, keep a healthy dose of skepticism, but remember that these statistics are the best we have. Although we cannot
take them completely at face value, they can provide us with a fair idea of conditions within a country or a region.
Throughout the semester, we will use these statistics to try to do just that.
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 fewer than 1000 people. Knowing the total population does not tell
a lot 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 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
Qatar (a Persian Gulf oil-rich country) is more than double the average income in the United States. However, with
about 300 million relatively affluent 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 Qatar, which has less than two
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 inexpensive supply of labor.
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 50 people per square kilometer.
Earth’s arithmetic density = 6.6 billion people / 130 million square kilometers
= 50 people / square kilometer
About 10% of the earth’s land surface is arable. The average arithmetic population density is about 500 people per
arable square kilometer. There are two ways to calculate this. The first way involves calculating the amount of
arable land and dividing that into the total population.
Area of Arable Land = Total Land * Percent Arable
Area of Arable Land = 130 million km2 * 10% arable = 13 million arable km2
Physiological Population Density = 6.6 billion people / 13 million arable km2
= 500 people / arable km2
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 = 50 people per km2/ 10% arable = 500 people per arable km2
Note: Physiological population density is always higher that arithmetic population density because the arable land
area is always less than the total land area.
Let’s look at Western Sahara. It has a simple population density of 2 people per km2. 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 40 million people. It has a total land area of 600,000 km2. About 8% of its total
land area is farmable.
Kenya’s Arithmetic Population Density = 40,000,000 people / 600,000 km2. = 67 people per km2
Total Farmable Land = Total Land * Percent Arable
Kenya’s Total Farmable Land = 600,000 sq. km. * .08 = 48,000 km2
Kenya’s Physiological Population Density = 40,000,000 people / 48,000 km2
= 833 people per arable km2
Kenya’s Physiological Population Density = 67 people per km2/ .08
= 833 people per arable km2
Explaining Arithmetic Population Density
Arithmetic population densities vary a lot across the world. Monaco (one of the smallest countries of Europe) has
the highest population density of any sovereign country, with almost 17,000 people per km2. Mongolia, dominated
by rugged mountains and cold desert and steppe climates, has the lowest population density of any sovereign
country, with less than two people per km2.
What accounts for the differences in population densities? Population density is a complex phenomenon. One of 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, which is located in Southeast
Asia. It is one of the larger islands of Indonesia. 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 the total land area that can be farmed. This is a
function of climate and of topography and rock type, which are 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.
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 people, 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. Wikipedia provides a list of
many of the world’s countries and territories sorted by size at
that some of the most densely populated countries are very small, but the most sparsely populated countries vary a
lot in size. The United States and Canada have similar sizes, but the population density of the U.S. is about ten times
greater than that of Canada – because the United States is more accessible and has more arable land than Canada.
Arithmetic population density alone does not tell us if a place is overpopulated. A place has too many people if there
are not enough available resources for them. This should raise a couple of questions. First, is the problem
overpopulation or over-consumption? Let’s look at water. People in the United States use more water than any other
people in the world – more than five times as much per person as the people of Great Britain. When we face water
shortages in the United States, is the underlying problem under-supply or is it over-use? Second, do the resources
have to be local or can they be imported? Singapore, located in Southeast Asia, has an extremely high population
density – almost 7,000 people per km2. Yet Singapore makes lots of money from trade and that trade relies on
Singapore’s high level of accessibility. Any food Singapore needs can be easily imported and Singapore can afford
to do so. Namibia is a fairly large country in southern Africa that is dominated by desert and steppes. It has about 2
people per km2. The country is poor and has poor interior inaccessibility. Namibia is therefore much more dependent
on local resources than Singapore is.
Throughout the last few centuries, the world’s population has steadily grown. In 2010, 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 2010 Population Data Sheet, the world crude birth rate is 20 and the crude death rate is 8. The total
population of the world is 6.9 BILLION. To calculate the total number of births and deaths in the world,
Number of Births / 6,900,000,000 = 20/1000
Number of Births = (6,900,000,000 * 20) / 1000
Number of Births = 138,000,000
Number of Deaths / 6,900,000,000 = 8/1000
Number of Deaths = (6,900,000,000 * 8) / 1000
Number of Deaths = 55,200,000
So in 2009, there should be about 138 million births around the globe – about the same size as the population of
Russia! During the same period, there should be about 55.2 million deaths – about the same size as the population of
the United Kingdom. The population of the world increased by almost 83 million – about the same number of
people that live in Germany.
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 = (20/1000) – (8/1000)
RNI = 12/1000
RNI = 1.2/100
RNI = 1.2%
The world is growing at a rate of 1.2% per year.
Doubling time 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 70 by the rate of natural increase. (70 is a constant. You just have to
memorize it. If you want to know where the 70 comes from, check out the following website:
DOUBLING TIME = 70 / RNI
For the world, the doubling time is
DOUBLING TIME = 70 / 1.2
DOUBLING TIME = 58 YEARS
So, if it continues to grow at the same rate, the world will have a population of 12.4 BILLION people by 2068!
That’s within your lifetime!
It is unlikely that the world RNI would remain the same
over the next 58 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, which is illustrated in the graph at
right. The Y-axis shows the magnitude of the CBR and
CDR. 40 is high and 10 is low. The X-axis represents
time. The red line represents crude birth rate and the
black line is crude death rate. The difference between the
two lines is natural increase.
Stage 1: Birth rates are high and death rates are high
(above 35). They cancel each other out, leading to slow
Stage 2: Birth rates are high, but death rates fall. 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 – around 10.
How can you tell which stage a country is in? The easiest way is to plot the birth and death rates on the graph. East
Timor, with a crude birth rate of 47 and a crude death rate of 21, is in the middle of Stage II. 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. The Democratic Republic of Congo (formerly Zaire) has the highest CBR,
at 50; Germany has the lowest CBR, 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. However, I don’t think access to birth
control is a highly important explanatory factor. The underlying assumption in the belief that access to birth control
means lower birth rates 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,
large families are desired and in countries where birth rates are low, large families are not desired. That is not to say
that there aren’t unwanted children but that is also true in countries where modern birth control is widely available.
Three factors do help explain birth rates: the percentage of farmers, pronatalist religions, and the presence of ethnic
Percentage of Farmers
Sitting in the United States in 2008, it is hard to imagine why some people want a large family. Children are
expensive. Typically, they are a drain on family resources. From the time they are born until their twenties, children
can cost their parents thousands of dollars per 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 retirement plans. Children are expected to care for their parents in their old age. If infant
mortality and other death rates are high, parents will want bigger families to insure that at least a couple of children
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.
You might wonder if all religions are pronatalist. After all, what kind of religion would be against birth? But the
question here isn’t if a religion is against birth, but if a religion actively promotes a traditional view that the ultimate
role of women is to be a mother. A pronatalist ideology asserts that it is a family’s duty to produce as many children
as possible and to pass the ideology onto the children. Quiverfull is an example of a pronatalist organization. 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
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.
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.
On the other hand, religion can have an important role in the number of births even in the face of other influences. In
the United States, Utah, which is predominantly Mormon, is the state with the highest birth rate. 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, Mormonism has an impact on birth rates.
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 of 1.2%. (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.)
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 42. War-torn Afghanistan also has a very high birth rate. The Democratic Republic of the Congo, with
the highest CBR, has faced brutal ethnic conflict for more than a decade.
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.
Countries with young populations tend to have higher 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. In the least
developed countries, over 40% of the population is 15 years old or younger. In these areas, the crude birth rate is
35. Developed countries are older, with only 17% of the population 15 years old are younger. In developed
countries, the crude birth rate is 11.
Explaining Death Rates
The average death rate around the globe is 9, but there is a lot of variation. The highest death rate, 30.8, is found in
Swaziland, a small country in Southern Africa. In the United Arab Emirates, however, only 2.1 out of every 1000
people dies each year. Four important factors contribute to death rates: the wealth of a country, how urban a country
is, the age structure of a country, the prevalence of infectious diseases and war.
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 the least developed countries it is
only 56 years. In more developed countries, only six out of every 1000 babies born dies before their first birthday. In
less developed countries, the infant mortality rate is 81.
Poor countries that have a high percent urban population tend to have lower death rates than poor countries where
the percent urban is low. This may be because it is easier to provide clean water and medical care to people who are
concentrated in urban areas than it is to provide them to a widely dispersed rural population.
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 per
year. This is true for much of the world. Older populations will have higher death rates and younger populations will
have lower ones. In Germany, 20% of the population is at least 65 years old. In spite of being one of the wealthier
countries in the world, Germany’s crude death rate is 10, which is 25% higher than 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 2.1.
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. Of 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.
War can also affect death rates and not just through casualties. War can make it harder to provide basic medical
services, sanitary facilities, and adequate nourishment. Diseases can spread more easily during wartime. The
deadliest epidemic of all time was the Spanish Influenza that killed between 50 and 100 million people worldwide
during World War I.
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 Spain, have a large positive net migration. Other countries, like Kyrgyzstan in Central Asia, 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. About 27% of the world’s population is under 15 years old while
8% is 65 or 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.
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 67. The average
female life expectancy is 71. In most countries of the world, females can expect to outlive men, but this has not
always been true. A hundred years ago, males outlived females because so many women died during childbirth. The
more developed a country, the greater the gap between male and female life expectancy. In the developed world,
male life expectancy is 74 and female life expectancy is 81. In the least developed world, male life expectancy is 55
and female life expectancy is 57.
In countries of Central and Southern Africa where high rates of HIV/AIDS are prevalent, life expectancy has fallen
to about 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
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 46. That means 46 out of every 1000 babies die before their first birthday – a bit
less than 2%. Infant mortality rate, like other statistics, varies widely from region to region. The lowest is Singapore,
with an IMR of 2.31. 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 if the IMR in Singapore included all births, it would
still be quite low. The highest IMR is found in Angola. Angola is poor southern African country. Although it is in a
relatively peaceful period, more than half of the population has been displaced by the civil wars that extended over
In general, countries that are wealthier, more urban and more stable 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
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.
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.