Completed cohort fertility

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Definition

General definition

The completed cohort fertility (CCF), also called the cohort completed fertility or completed fertility rate (CFR) for a cohort of females (typically, a birth cohort) who have all completed their childbearing years is the arithmetic mean of the values of completed fertility for all females in that cohort.

For a given birth order

Suppose i is a positive integer. The completed cohort fertility at birth order i for a given birth cohort is the fraction of people in that birth cohort that have a birth at birth order i.

Variants

Completed fertility rates can be computed only for cohorts that have completed their childbearing years. This creates a huge time lag: we can only calculate completed fertility rates for cohorts that were born 49 or more years ago.

Some sources, such as the Human Fertility Database, provide a piece of information called CCF40: this is the parity at age 40 for the cohort. This may also be broken down by birth order.

Data

Data collection challenges

There are two main disadvantages of CCF relative to other types of fertility data such as the total fertility rate:

  • CCF is available only after a time lag. We can calculate CCF only for birth cohorts that have completed their childbearing years, which means birth cohorts that were born at least 49 years ago. This is so even though most women have babies before the age of 40. Note that the related measure CCF40 overcomes this problem, but this data is also lagged and fails to adequately capture what is happening to fertility at present.
  • Computation of CCF data requires considerably more demographic information than computation of the total fertility rate.

Broadly, there are two ways that CCF data could be measured:

  1. Direct measurement: For all births, the birth cohort of the mother at the time of birth is recorded. Thus, it is possible to put together the data and calculate the total number of children had to women from a particular birth cohort.
  2. Estimation: Surveys are used based on appropriate sampling methodology and the results are interpreted.

Data sources

Data source Data available
United Nations data No direct data available
Gapminder (synthesis of data from multiple sources) No direct data available
Human Fertility Database CCF and CCF40 data available for some OECD countries. Last year for CCF data is the 1960 birth cohort and last year for CCF40 data is the 1969 birth cohort. For some years, the data is available by birth order as well. The country list is Austria, France, Norway, Switzerland, Bulgaria, Germany, Portugal, Taiwan, Canada, Hungary, Russia, U.K., Czech Republic, Japan, Slovakia, U.S.A., Estonia, Lithuania, Slovenia, Ukraine, Finland, Netherlands, Sweden