The data collected in a census snapshot can be represented and analysed in different ways, The most common means of analysis are the Population Pyramid and the Demographic Transition Model (DTM).

A Population Pyramid shows the population structure of a country. This information is captured for a single point in time. It shows, at a glance, the relationship between the number of males and females and their age profile. Over time, the shape will change to reflect the structural changes.

The DTM, on the other hand, is a generalised model of population change over time. This is based on the pattern of changes in birth and death rates, as a country develops.

Both models can be used for comparing countries as well as reviewing past trends and projecting future structures. Governments can use this kind of information to help plan economic and social policies.

We have Data Files for our ten chosen countries. Each has key population data . You can study these and see how the graphic tools can be used to help understand the data. You may wish to print these to match up with the Country Profiles from the Collecting Data section.

You'll notice that, for each country some figures vary – especially the total population! This happens because the tables and diagrams are taken from different sources and the material will probably have been collected in different ways at different times. Even so, clear patterns and trends emerge. You can find out more about the challenges of collecting information in the Collecting Data section.