Module 5 - Data

Slide 1

Population calculations help to explain issues that affect world hunger and how hunger affects the world's people. In this section we will examine some of the calculations that may be useful as you read course materials and other information on world issues. The data used in these calculations are from the Population Reference Bureau. These data are updated annually. We are using the 2003 data for illustration. You may want to print out a copy of the current data to follow the calculations and to see how the data are changing.

Slide 2

Population estimates describe numbers of people in different categories. The current world population is around 6 billion people.

Over a third of the world's population lives in China and India. These are both Asian countries. These large populations require a lot of food and other resources. How would a large decrease in their productivity affect the remainder of the world?

Slide 3

Many governmental and non-governmental agencies try to predict population growth to project future needs. The most simple calculation to do this is the natural increase (%), which is based on current birth and death rates. Factors that alter the birth and death rates would affect population growth and future resource needs.

Which population is growing faster: the population in less developed countries or the population in more developed countries?
The population in less developed countries is growing faster because their Natural Increase (%) is greater.

Which factor currently has the greater effect on natural increase: birth rate or death rate? [Hint: where do you see the greater difference in rates between more developed and less developed countries on the Population Reference Bureau tables?]
Currently the birth rate has a greater effect. This is because there is generally a greater difference in the birth rates than in the death rates. This is variable, though.

International health organizations are concerned about many health issues. Two that greatly affect natural increase are the spread of HIV/AIDS and use of contraceptives. How would each of these affect natural increase (%)?

Slide 4

What is the population doubling time for the US?
     U.S. = 70/.6 = 116.7 years; In a century, the U.S. will have approximately 1 doubling.
How many people is this?
     1 doubling = 21 = 2x as many people; There are about 290 million people in the US today?580 million in the next century

What is the population doubling time for Africa?
     Africa = 70/2.4 = 29.1 years; In a century, Africa will have approximately 3 doublings.
How many people is this?
     3 doublings = 23 = 8x as many people; There are about 885 million people in Africa today? over 7 billion in the next century [This is more than the total population of the world today.]

Slide 5

Infant mortality rate is a major baseline measure for a country's health. In general, more developed countries have lower infant mortality rates than do less developed countries. Part of this is because of good general health and nutritional status. Part of it is because of medical care during pregnancy, delivery, and early infancy.

Asia: 54 per thousand = (54/1000) x (100) = 5.4%
Africa: 88 per thousand = (88/1000) x (100) = 8.8%
North America: 7 per thousand = 0.7%
Europe: 8 per thousand = 0.8%

Slide 6

For this indicator, international dollars indicate the amount of goods and services one could buy in the US with a given amount of money. This is calculated by dividing the purchasing power of the country by its population.

The US has a relatively large amount of purchasing power and a relatively small population. This means that, on average, individuals have greater purchasing power.

Africa has a relatively small amount of purchasing power and a relatively large population. This means that, on average, individuals have less purchasing power.

Based on natural increase, how would you expect the GNI PPP for the US and for Africa to change over the next century? What could affect this projected change?

Slide 7

The age dependency ratio is the simplest projection of development potential. It describes the percentage of the population that is relatively unproductive. The smaller the age dependency ratio, the greater the potential productivity of the population. It is certainly possible to have people in the 15-65 year age range who are not productive. This is an estimate that does not include this factor.

HIV/AIDS is rapidly increasing the age dependency ratio in some parts of Africa (decreasing potential productivity). This is because many of the young to middle-aged adults are infected and die, leaving children behind. The age dependency ratio shows the effect of having a child-dominated society. It does not show the reduced productivity of individuals who are sick and the further reduction of productivity of the remaining population when they require care. It further does not show the decrease in productivity when children cannot grow as much or as varied a food supply, which can increase malnutrition.

Slide 8

Life expectancy at birth gives another general indicator of a country's health. The range is very wide, showing cumulative effects of poor health care, wars, etc.

Slide 9

Means are averages that are frequently used to describe the general status of a population.

Calculated means frequently differ from reported mean because calculations are based on rounded figures.

Slide 10

The mean is an average, which means it takes into account all of the actual values. Very high or very low values can greatly affect a mean.

A median is not affected as greatly by a single high or low value.

Slide 11

True population projections are difficult to make with accuracy. The simplest, natural increase (%) assumes that birth and death rates remain constant. This is seldom a good assumption. While it is easy to talk about factors that might affect population projections, creating a mathematical model is more difficult because you have to estimate each factor and the ways in which factors interact.

Similarly, it is difficult to project food production. Many factors, including availability of land for farming, development of farming methods, numbers of farmers, development of new foods, etc. affect the amount of food that can be produced.

World hunger, then, has some very complicated calculations: how much food? how many people?