The criterion used to place respondents into the classification is the number of children ever born alive to them.
Fertility is a flat classification in number of children categories from no children to nine children plus a category for ten or more children. The classification has 11 categories excluding residual categories.
The residual categories are defined in Glossary and references.
The full classification is available in the 'Available Files' section on the main page.
The input variable for coding is the number of children born alive as specified on the questionnaire. If the number of children born is ten or more, then this should be coded to category 10 (ten or more children).
Imputation is not recommended for this variable. As there is an option to object to answering this question there is no obvious or logical way to reassign 'not stated' or 'object to answering' responses to a numerical category.
All fertility measures listed in the definitions section (except number of children born alive, number of registered live births and number of registered confinements) are derived variables. They often use birth registration data in combination with resident population estimates and/or number of children born alive data. The process for deriving these fertility measures is subject to best practice at the time and is not listed in this standard.