If the brother or sister is alive, you must record their age at their last birthday. If the respondent doesn't know, persist by asking by how many years the brother or sister is younger or older than the respondent.
The ages of sisters who are still alive are used for calculating the years of exposure for estimating maternal mortality rates. After recording the response, go to the next column (if there are other brothers or sisters).
Source of information
Head of household or other responsible household member