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3301.0 - Births, Australia, 2011 Quality Declaration 
Previous ISSUE Released at 11:30 AM (CANBERRA TIME) 25/10/2012   
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TECHNICAL NOTE EFFECT OF PREVIOUSLY UNPROCESSED NEW SOUTH WALES BIRTHS


INTRODUCTION

1 Questions have been raised over the completeness of New South Wales (NSW) birth counts in recent years. In response to these concerns the ABS, in conjunction with the NSW Registry of Births, Deaths and Marriages, has undertaken an investigation which has led to the identification of an ABS systems processing error. The ABS acknowledges that this has resulted in previous under coverage of births in NSW.

2 Data for 2011 have been corrected to ensure that NSW birth and fertility statistics released in this publication are correct. This has resulted in an additional 5,179 records to the NSW birth count for 2011, of which 1,215 (or 23.5%) are Aboriginal and Torres Strait Islander births. The ABS understands that this error has occurred since 2005 and will be undertaking further investigations to determine the appropriate action that is required.

3 The error has only affected births that were registered in NSW, of which in 2011, only 72 (or 1.4%) were to mothers who were usual residents of another state or territory. As a result, inclusion of the previously unprocessed births in 2011 will mostly affect the fertility statistics of NSW, and to a lesser extent those of Australia. This analysis therefore examines the impacts of these births on fertility rates of NSW and Australia. Further, since Aboriginal and Torres Strait Islander births are over represented in these additional births, the impact on fertility rates of Aboriginal and Torres Strait Islander women is also examined.


EFFECTS ON FERTILITY RATES

4 Total fertility rates (TFR) for NSW and Australia may have been underestimated in recent years as a result of fewer births being processed by the ABS than were actually registered. In 2010, the NSW TFR was 1.87 births per woman. The inclusion of the previously unprocessed NSW births in 2011 increased the NSW TFR to 1.91 births per woman, which would have declined to 1.81 births per woman if the previously unprocessed births had not been included.

5 Prior to 2005, the TFR for NSW had consistently been higher than the TFR for Australia. However, this trend has reversed during the period from 2005 to 2010. The NSW TFR has risen again above the TFR for Australia in 2011 as a result of including the previously unprocessed births. This suggests that the unprocessed births for NSW may have caused the NSW TFR to incorrectly be below the Australia level since 2005. This will be confirmed once the unprocessed births for earlier years have been investigated and processed.

Total fertility rate(a), all women - 2001 to 2011
Graph: Total fertility rate(a), all women—2001 to 2011


6 The pattern of fertility for Australia mirrors that of NSW due to NSW being the largest contributor to the birth counts of Australia. Inclusion of previously unprocessed births do not change the pattern of fertility rates in either NSW or Australia. However, they do slightly increase the level of fertility for each age group suggesting the fertility rates may have been under estimated in recent years.

Age-specific fertility rate (a), all women - New South Wales
Graph: Age-specific fertility rate (a), all women—New South Wales



EFFECT ON MEDIAN AGE OF MOTHER

7 The inclusion of the previously unprocessed births has caused the median age to decline slightly in both NSW and Australia. This suggests that the median age in recent years may have been over stated. This will be confirmed once the unprocessed births for earlier years have been investigated and processed.

Median age of mother, all women - 2006 to 2011



EFFECT ON ABORIGINAL AND TORRES STRAIT ISLANDER WOMEN FERTILITY RATES

8 In 2011, the TFR for Aboriginal and Torres Strait Islander women in NSW has risen above the Australia level after consistently being lower in previous years. The reversal of the trend may have occurred before 2011 if the unprocessed births had been included in TFR calculations. This is because the number of previously unprocessed births as a proportion of total Aboriginal and Torres Strait Islander births is much larger for NSW than for Australia and thus has a greater impact on NSW fertility.

Total fertility rate(a), Aboriginal and Torres Strait Islander women - 2001 to 2011


9 The age-specific fertility rates for Aboriginal and Torres Strait Islander women in NSW best demonstrate the effect of the previously unprocessed births on the level of fertility for this state (see graph below). Although the pattern of fertility in NSW does not change, the fertility level has increased in each age group with the inclusion of these births. The same is true for Australia (not shown in the graph).

Age-specific fertility rate (a), Aboriginal and Torres Strait Islander women - New South Wales
Graph: Age-specific fertility rate (a), Aboriginal and Torres Strait Islander women—New South Wales



EFFECT ON MEDIAN AGE OF ABORIGINAL AND TORRES STRAIT ISLANDER MOTHERS

10 The inclusion of the previously unprocessed births has caused the median age to decline slightly in both NSW and Australia. This suggests that the median age in recent years may have been over stated. This will be confirmed once the unprocessed births for earlier years have been investigated and processed.

Median age of mother, Aboriginal and Torres Strait Islander women - 2006 to 2011



CONCLUSION

11 The level of fertility, particularly for Aboriginal and Torres Strait Islander women, in NSW has increased with the inclusion of the previously unprocessed births. However, the pattern of the fertility rates across the age groups of mothers in NSW has not changed. The exclusion of these births may have resulted in an under estimation of fertility rates in NSW and an over estimation of median age in recent years. This will be confirmed once the unprocessed births for earlier years have been investigated and processed.


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