So this is Census day!

Well the day is finally here! The one day every 5 years we get to fill in our Census forms and contribute to the statistical picture of the nation for the next 5 years. Whether you’re submitting your form by eCensus or the regular paper form, whether you’re at home, staying at another house or a Non-Private Dwelling on Census night, the information you provide will help shape Australia into the future.

As you sit down to fill in your form, think about your answers. Answer truthfully remembering that whatever you put here will represent you statistically for the next 5 years worth (and if you are marking the time capsule box to retain your record in the National Archives, much longer than that).

But Census is a bit like Quantum Physics – the measurement can cause changes in the output! Even with everyone filling in their Census accurately, there are some things about the day, and time of year, which can affect the Census results.

The weather on Census day

The weather on and around Census day can have a surprising effect on the Census. Apart from the fact that Census collectors find it hard to deliver and collect forms in the rain, miserable weather can have an impact on answers to the questions. Question 45 asks “How did the person get to work on Tuesday, 9 August 2011?”. Our online demographic profiles show this under “How do we get to work?“. If it is raining on the day, there are likely to be far less people riding their bike to work (90,000 people in 2006) than if it’s a fine sunny day. It may affect public transport use as well. We treat this output as the broader characteristics of the population, but it is worth remembering that some questions like this only relate to the one day.

For the record, 2006 Census was in a drought year (for SE Australia), and it was a balmy 20 degrees in Melbourne, very warm for August.

As at the time of writing, the forecast for Melbourne looks very different for this in 2011, with rain and cold winds forecast. I will update with a comment on the day.

The weather can also affect the number of people who are away from home on Census night – particularly on the Victorian/NSW snowfields. If it’s a good snow season and a good week for snow, there will be more people counted in the ski resorts.

It really is worth remembering the weather on the day, so to this end, we are inviting all our blog readers to please submit your local weather report for Census day from your part of Australia. Let us know what the weather is like there!

The time of year

Census is done on a Tuesday night in winter outside school holidays to maximise the number of people who are at home.

But if there are any major events on in an area during the Census week, this can cause more visitors to particular cities, and therefore more people to be away from home.

It is also peak tourist season in some Queensland coastal areas, and the lowest season in Victorian and southern NSW coastal resorts.

Also, some questions like Q44 about the number of hours worked by employees relate to the week prior to Census. If it’s a year with a lot of illness and people away from work sick, the number of hours can actually go down because it relates to this specific week. From this we derive information about full/part time workers.

The Aussie dollar

Anecdotally, it seems that everyone is taking advantage of the high Australian dollar at the moment and going overseas on holiday! Though it is traditionally the time of year when most people are at work, the cold weather and higher purchasing power overseas may entice people away from our shores.

Those who are overseas on the night are not counted in the Census data for this year, though they are added back into the official population counts by using data from passenger cards.

So will there be more people away on Census night 2011 due to the high Aussie dollar?

For those who are in Australia but away from home, you fill in the form wherever you are tonight. It used to be that you would always be counted in that place “Place of enumeration” in all the output datasets. But now that many of the datasets are based on place of usual residence, this isn’t as much of a consideration.

So when you fill in your Census form, take some time to reflect on where the data goes from here, and how it represents you statistically over the next 5 years (Remember of course that no information about individuals is released by the ABS or .id, who only provide data in aggregate).

Happy Census Day!

PS: Don’t forget to let us know what the weather’s like where you are today. Oh, and you might like to subscribe to our blog for updates about when the Census data will be released.

.id is a team of population experts who combine online tools and consulting services to help local governments and organisations decide where and when to locate their facilities and services, to meet the needs of changing populations. Access our free demographic resources and tools here.