Census reveals dramatic changes in Canterbury

The 2013 census has revealed some marked changes in the demographic structure of our region since the last census, in 2006, according to Dr MALCOLM CAMPBELL and Dr JOHN McCARTHY.

The census has provided a formidable "snapshot" of the population of our country. The most recent census was completed on Tuesday, March 5, 2013, and the results have been eagerly anticipated as they offer the most detailed insight into the population of New Zealand since the previous census of 2006.

It is useful to know about the age structure of the population of an area, something that the more detailed census data allows us to do. How many 30-year-olds are there? Are they men or women? Are there more of them than several years ago?

This information is valuable. People can act very differently, and can have very different needs, depending on how old they are and whether they are men or women.

The number of babies being born, the number of people dying, and the number people moving around are greatly affected by the age structure of a population.

For example, people are more likely to leave home and move elsewhere when they become adults, generally to study away from home or to enter the job market. A female aged 25 is more likely to have a child than a female aged 55. People are much more likely to retire at age 65 than when they are 25 years old (unless they are very lucky).

To state the obvious, different people do different things at different times. As a country, we need to understand just how different the people are across each area, so that we can plan accordingly.

Do we need more school places, or more retirement homes? Or do we need both?

The census provides the information which helps us to begin finding answers to these types of question and to make educated decisions for the future.

There is the added issue that as time goes by, areas change (and some change more than others) but that is a story for another day.

How has Canterbury changed over the last few years?

The story for today is how the age structure of our region has changed in the seven years between 2006 and 2013, and the evidence is remarkable.

Events have occurred in recent years which have reshaped the physical and social landscape of the region, for example, where some of us live, work and play.

We can now start to understand just how much things have changed for us all as well as where.

If we look at a visualisation of the population of our region, we notice how, over the past few years, some important changes have occurred.

These types of visualisations are normally called population pyramids.

If we look at a specific example, there is an increase in men aged 20 to 24 in Canterbury, just over 1700 more. Unfortunately for the young men, the females aged 20-24 have the same numbers as in 2006. Depending on your point of view, this either means unlucky young men or perhaps lucky young women. Dating strategies may have to adjust across the region.

Canterbury as a whole has also lost men and women around the ages of 30 to 44 as well as children. We could speculate as to why this might be the case, given recent tectonic events. Interestingly, Canterbury has grown in the number of people aged over 50.

This means on average we are getting older. The biggest increases in population are those men and women aged 65 to 69 years old.

We can see that populations are dynamic and mobile over time. Population dynamics are just one of the many subjects geographers study. We call this study demography; using numbers to study human populations.

The change isn't equally spread across men or women, or across people of different ages and this has important implications for Canterbury.

Like the ancient Egyptians, we construct pyramids but of a rather altered form and for a different reason, to see how the population of our region is changing.

Dr John McCarthy is a postdoctoral research fellow at the GeoHealth Laboratory at the University of Canterbury. Dr Malcolm Campbell is director of the GeoHealth Laboratory and a lecturer in health geography at the University of Canterbury.

The Press