Dr Lisa Denny: Demographer
  • Home
  • About Lisa
  • Publications + Presentations
  • Contract Research
  • OpEds

explaining why Tasmania's population is projected to decline

27/11/2013

4 Comments

 
Yesterday the ABS released their population projections for Australia and the states and territories for the period 2012 to 2101.  Under the medium growth scenario (Series B), Australia is projected to double the size of its population to 46 million by 2075, however, under the same medium growth scenario, Tasmania's population is projected to firstly increase slowly before leveling out by around 2046 and then decreasing marginally from 2047 onwards. 

While population projections are not intended to be predictions or forecasts (as I have explained in a previous blog), they are illustrations of growth and change in the population that would occur if assumptions made about future demographic trends were to prevail over the projection period.

Population change is a complex process, particularly in Tasmania's case, so I will use this blog to explain (as simply as I can) why Tasmania's population is likely to decline in the future. 

The two correlates for population growth are the size of the reproductive cohort[1] and economic performance, neither of which are working in Tasmania's favour at the moment (however, there are early indications that the economy is at a turning point).  Both these correlates are influenced by the age profile of inward and outward migrants from interstate and overseas.   

Size of Reproductive Cohort
Until 2012, Tasmania had the highest Total Fertility Rate (TFR) in Australia, averaging above the population replacement rate of 2.1 births per woman in her lifetime since 2005.  However, it is important to understand that a high TFR does not necessarily automatically translate into an increase in the number of births (see this previous blog).  The TFR is a synthetic measure, being the sum of the age-specific fertility rates at a point in time (calculated as the number of births per 1000 women in five year age groups).  The TFR does not take into consideration the size of the reproductive cohort (the number of women of childbearing age). 

In Tasmania, the size of the reproductive cohort has been declining both numerically and structurally (proportionately) since the largest birth cohort was born in the early 1970s.  This decline in the size of the reproductive cohort is influenced by two compounding factors.  First, a decline in the TFR (consistent with Australia and other developed nations) which until the early 2000s was persistently below the population replacement rate, and, second, persistent Net Interstate Migration (NIM) losses in the prime reproductive ages.

These factors result in a smaller proportion of women in the population of childbearing age, as reflected in the population age structure (see diagram below).  As a result the number of children being born in Tasmania is on a downward trajectory, despite a recent upturn in the early 2000s. 

Economic Performance
Popular consensus is that the rate of population growth is influenced by the economic conditions of the state at the time and that a return to positive economic performance will reverse the current downward trajectory of the rate of growth. This is partly true, however, the rate of growth is dependent on the relative economic performance of the state compared with Australia, or even other states. 

Tasmania’s greatest rates of annual population growth occurred when the state’s economic performance exceeded the national rate, most recently from 2002 to 2004.  However, as soon as Australia’s rate of economic growth surpasses that of Tasmania the state’s rate of population growth declines.  This is directly attributable to the relative perceived and actual opportunities available elsewhere and resulting NIM losses.  As such, in circumstances where Tasmania’s economic performance is not equivalent to other states and/or territories (even if positive), NIM losses in the working and reproducing ages will likely increase, creating the domino effect of decreases in the number of births, and as a result the rate of population growth will decline. 

For this reason, a reliance on a return to positive economic growth will not result in a significant reversal in the current rate of population growth in Tasmania.  In fact, without intervention, it has the potential to hasten the process to a scenario of population decline.  This is attributable to the fact that the organic growth which occurs as a result of positive economic performance is due to (net) growth in older age groups (based on historic trends).  So while in the short term, population growth occurs, over the longer term, the resulting acceleration in the rate of ageing will bring forward the point of the end of growth and population decline (as there will be more deaths than births). 

Summary
Given that the two correlates for population growth are not working in Tasmania's favour, and are further negatively impacted by the age profile trends of inward and outward migrants (both interstate and overseas), it is unlikely that Tasmania's population will increase over the longer term.  Moreover, without a level of strategic intervention, it is likely that Tasmania's population will eventually enter a state of decline. 






[1] In terms of calculating the Total Fertility Rate (TFR) the reproductive cohort includes all women aged 15 to 49 years, however when considering potential for population growth the reproductive cohort can be further defined as the ‘prime reproductive cohort’ which is those women aged 20 to 39 years.

Picture
4 Comments
JB
27/11/2013 11:29:31 am

Hi Lisa,
There is a sharp peak of 40 year old men and slightly older women. Is this statistically significant, and if so, why?

Reply
Lisa
27/11/2013 12:29:58 pm

Hi JB, the diagram represents the actual population by age and gender as such statistical significance is not relevant when using population level data.

There are a number of reasons why - the large baby boomer cohort, the baby bust period when the leading baby boomers started having children (before the fertility rate dropped below replacement rate in around 1972) and most significantly the age profile of interstate migrants - gains in older ages adding to the top of the age structure and losses in the younger ages creating the bite in the age structure from 20 to 40 years which creates the continued tappering in at the bottom of the age structure as there are less people having children (and the fertility rate was persistently below the replacement rate of 2.1 births per woman).

I trust this makes sense.

Cheers, Lisa

Reply
harini link
22/12/2015 04:27:41 pm

Thanks for your valuable posting.I have collected more than information from your website.I Am working in <a href="http://www.excelanto.com">Erp Software Development Company In India</a>.Here providing very low price and Quality ERP, Cloud ERP, CMS, responsive web design and ERP. You have any more than information kindly make me call to this number 044-6565 6523.

Reply
campus events link
17/2/2017 05:42:34 pm

Thanks for your great information. Sign up and Register Your Events Today!!!!!!!
<a href="http://www.campus.events">Online Event Registration websites</a> | <a href="http://www.campus.events">Upcoming Events & Fests in india</a>

Reply



Leave a Reply.

    Archives

    April 2023
    September 2022
    August 2022
    July 2022
    June 2022
    April 2022
    March 2022
    December 2021
    July 2021
    June 2021
    February 2021
    November 2020
    September 2020
    August 2020
    June 2020
    October 2016
    July 2015
    June 2015
    March 2015
    December 2014
    November 2014
    October 2014
    August 2014
    June 2014
    May 2014
    April 2014
    March 2014
    February 2014
    January 2014
    November 2013
    October 2013
    September 2013
    August 2013
    July 2013
    May 2013
    April 2013
    February 2013
    January 2013
    December 2012

    Categories

    All
    Births
    Confidence
    Deaths
    Demography
    Economic Growth
    Economic Performance
    Economics
    Education
    Employment
    Gen Y
    Labour Force
    Leadership
    Migration
    Population
    Population Ageing
    Population Growth
    Pride
    Productivity
    Tasmania
    Total Social Production
    Vital Index
    Youth
    Youth Unemployment

Powered by Create your own unique website with customizable templates.