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KID1STBIRTHCMC
First child birthdate in century month
Group: Fertility

KID1STBIRTHCMC is a 4-digit variable that represents the century-month value (months since 1900) of the woman's first live birth. The following values represent NIU (not in universe) or missing cases:

9000 = Logical edit - missing
9995 = Not interviewed (female questionnaire)
9996 = Not interviewed (household questionnaire)
9998 = No response or missing
9999 = NIU (not in universe)

Description

KID1STBIRTHCMC reports the century month code (CMC) for the month and year of the woman's first live birth.

Note that January is consistently the most common month across samples (see KID1STBIRTHMO). Due to the data entry format of the survey, if a respondent reported a year but not a month for her first live birth, January was the default month. Also due to the data entry format, if a woman skipped the question, the default date was January 1st, 2021. IPUMS has recoded these cases to "No response." Additionally, IPUMS-PMA has recoded years that were in the future at the time of the interview as "Logical edit - missing." For example, values of 2018 or later in samples from 2016 have been recoded. For some samples, interviews were conducted across two years, for example, some 2016 samples include interviews from early 2017.

Century month codes (CMC) are particularly useful for checking the consistency of dates, calculating intervals between events, and imputing dates when the information for an event is missing or partially complete.

Century month codes (CMC) are calculated by multiplying by 12 the difference between the year of an event and 1900. The year 1900 was chosen as the reference period because all of the relevant events for PMA2020 occurred during the twentieth or twenty-first centuries. The month of the event is added to the previous result.

CMC = (Year - 1900) * 12 + Month
For example, the CMC for June 2002 is:

CMC = (2002 - 1900) * 12 + 6 = 1230

In other words, 1,230 months have elapsed between January 1900 and June 2002. Starting with CMC figures, one can calculate the month and year using the following formulas:

Year = int( ( CMC - 1 )/12 ) + 1900

[int(x) is the integer part of x]

Month = CMC - ( ( Year - 1900 ) * 12 )

The information above is based on "Online Guide to DHS Statistics" (Rutstein and Rojas, 2006).

The question associated with this variable was included in the female questionnaire.

Comparability

There are no comparability issues.

Universe

  • Women age 15-49 who have ever given birth.

Availability

  • Burkina Faso: 2014-2017
  • Congo (Democratic Republic): 2014-2017
  • Cote d'Ivoire: 2017-2018
  • Ethiopia: 2014-2018
  • Ghana: 2014-2017
  • India: 2016-2018
  • Indonesia: 2015-2016
  • Kenya: 2014-2017
  • Niger: 2015-2018
  • Nigeria: 2014-2018
  • Uganda: 2014-2018