Re: IDHS 2017 [message #29363 is a reply to message #29356] |
Thu, 06 June 2024 11:26 |
Bridgette-DHS
Messages: 3199 Registered: February 2013
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Senior Member |
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Following is a response from Senior DHS staff member, Tom Pullum:
I just looked at the PR and KR files, which normally would include day of birth for children under 5. You are right, day of birth is missing, but day is included for the date of vaccinations.
The omission of day of birth for children under 5 may be due to the fact that this survey did not include anthropometry. For the calculation of the HAZ, WAZ, and WHZ it is essential to be able to calculate days of age (as date of measurement minus date of birth). But I wish it had been included! Soon after that survey, DHS started including day of birth for ALL births in the birth history.
I confirmed that age in years (b8) was calculated as int((v008-b3)/12). Here, v008 is the cmc of interview and b3 is the cmc of birth. This calculation ignores the day of the interview (even though it is available) as well as the day of birth (which was omitted). The assumption in this calculation is that the day of birth is between 1 and the day of the interview, inclusive--that is, if the month of interview is the same as the month of birth, the child has already had the birthday by the date of interview.
I could suggest a way to impute the day of birth, and then calculate a cdc, but I hesitate to do this. The hepatitis B birth dose is supposed to be within 24 hours of birth. The day of that dose may well provide the best estimate of the day of birth. An imputation procedure could not legally produce a birth day that was AFTER the date of the first immunization. Sorry I can't be more helpful.
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