Demography: Introduction

This is Susanne. Her job is to plan what kinds of building should be built in the city where she lives. She works as: a city planner. Susanne is inspecting a plot the city has bought. But what should be built?

The city's inhabitants are of different opinions. Jenny dreams of living in a big house for young people when she is old enough to leave home. There needs to be a rehearsal studio! John wants a new school to be built on the plot Susanne is inspecting. Then his children won't need to travel so far in the mornings!

And Cecilia thinks that there is a shortage of apartments that suit the needs of the elderly. There is a need for a house with an elevator and a garden! All ideas are possible to carry out. But planning a construction project takes time. It can take many years to get all the decisions in place and until a building is finished.

By then Jenny will be a grown-up woman. John's children will have left school. And Cecilia, well, she might not even be alive. To make a decision, Susanne needs to learn more about the city's inhabitants. Not only those who live in the city right now -- but also about those who will live there in the future.

Susanne needs the help of demography! The word demography comes from Greek. Démos means people -- and gráfo means description. Demography is what we use when we want to describe a population. And for that we need facts and figures: we need statistics!

In most countries, government agencies collect information about the people who live there. The number of births... The number of deaths... How many move in and out of the country... Where people live: their address...

How many are studying, are unemployed, have jobs -- their occupations. and much more! All this information is saved in registries. But it takes a lot of effort to construct accurate registries. In poor countries with many inhabitants, or countries where there is war, statistics are often missing.

To learn more about the population the State can conduct a census. In the world's most populous country, China, a census was conducted in 2010. Six million people made calls or knocked on doors to ask questions about each household. How many people live at the address, how old they are, what gender they are, and about their level of education. When the census was finished...

they had counted one-point-three-seven billion people. Oh, right! We were supposed to help you! In the city where Susanne works, accurate registries have been kept for a long time. That means we know quite a lot about those who live in the city right now -- and about those who have lived there in the past.

With the help of these statistics we can try to predict who will live in the city in the future. We can make a forecast. When we make forecasts, we look at statistics and try to see patterns. We try to understand how what has happened in the past might influence what will happen in the future. That is what we need to do now.

In the registries we find statistics from the last few years: Every year fewer and fewer children are born. Most young people move away from the city after leaving school. And the retired? In this city, people live to become very old. Most of those who move to the city from other places are also retired people.

Now we can make a forecast. Are you with us, Susanne? Not many children are being born. This means there'll be no need for more schools in the future. Many young people leave.

This means a big house for young people would probably not be fully used. We know that people grow very old... And that retired people continue to move into the city. This means that the number of elderly people will grow, while the proportions of children, and young people will go down. The city has an aging population.

In the future, there'll be a need for housing that suits the needs of elderly people. So, Susanne will plan for more buildings with lifts -- and gardens! And maybe a studio too.