Methodology

The BIRTH BAROMETER was first launched in May 2010 as Geburtenbarometer Austria and Geburtenbarometer Vienna, two interconnected projects of the Vienna Institute of Demography (VID).
The project aims to analyse period and cohort fertility trends in Austria and in Vienna. It has three main objectives:

• Monitoring recent fertility trends in Austria and Vienna on an annual, quarterly and monthly (for Austria only) basis.
• Providing a set of parity-specific fertility indicators that are less affected by the ongoing changes in fertility timing than the commonly used period total fertility rates (TFR).
• Providing detailed data on annual and cohort fertility developments, including expanded data on male fertility, fertility timing and migrant fertility.

Fertility indicators are computed from the extracts of individual birth records supplied by Statistics Austria. All computations are carried out by the VID team. Some indicators can slightly differ from the official values published by Statistics Austria.

Regularly updated annual, quarterly and monthly data provided by the BIRTH BAROMETER allow the evaluation of most recent fertility trends, which can be analysed in conjunction with the changes in family policies and socio-economic indicators. The BIRTH BAROMETER features the period Total Fertility Rate (TFR) as well as the set of Parity Progression Ratios (PPRs) based on birth intervals (duration since a previous birth). A summary indicator of fertility derived from these Parity Progression Ratios is termed the Period Average Parity (PAP). The PAP has two main advantages when compared to the conventional TFR. First, it is relatively little affected by the changes in the timing of births, especially the long-standing shift to a later age at childbearing. Second, its computation from the PPRs is consistent with the sequential nature of childbearing and thus approximates more closely the family-building behaviour of real birth cohorts.

Completed cohort fertility, cohort childlessness, and parity composition, has been calculated using Census 2001 results, combined with age-specific fertility rates from 2001 onwards.

The data cover all live births born in Austria in a given year. Since 2015, they have included a small number of births to Austrian citizens abroad (740 in 2015; 619 in 2016; 646 in 2017; 731 in 2018).
The data on age are specified by age reached during the year (ARDY). Only 5-year age groups are specified by age in completed years (ACY).
The age-specific fertility rates are computed as a number of live births per population of a given age. They reflect the fraction of women (or men) who have a child at each age. In the case of 5-year age groups, the result is multiplied by 1000 and the resulting fertility rates are expressed per thousand women or men.
Mean age at birth is computed from age-specific fertility rates across all reproductive ages and not from the distribution of the numbers of live births by age. The indicator derived from the rates by age is not affected by the changes in female population by age.
All data are complete, pertaining to the entire analysed population in a given territory (Austria, Vienna). There are no unknown cases except for the data on fathers and male fertility. Some records on live births have missing information about father. Father was unknown in 4686 cases in 2015 (5.6%); 4483 cases in 2016 (5.1%); 1344 cases in 2017 (1.5%); and 1150 cases in 2018 (1.3%).

For more details on methods see the publications.