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Date started living with first husband or partner in century month

COHAB1STSTARTCMC is a 4-digit variable that represents the century-month value (months since 1900) when the woman began living with her first partner or husband. The following values represent NIU (not in universe) or missing cases:

9995 = Not interviewed (female questionnaire)
9998 = No response or missing
9999 = NIU (not in universe)


For women who have been married more than once, COHAB1STSTARTCMC reports the century month code (CMC) for when the respondent started living with her first husband or partner.

Note that January is consistently the most common month across samples (see COHAB1STSTARTMO). Due to the data entry format of the survey, if a respondent reported a year but not a month for when she started living with her first husband or partner, January was the default month.

Enumerators were instructed to enter the date as January 1st, 2020 (January 1st, 2030 for samples in 2019 or after) if the respondent did not give a response to the associated survey question. IPUMS has recoded these cases to "No response or missing."

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, using the following formula:

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.


In some samples, enumerators are instructed to confirm the respondent's answer if she reported living with a husband or partner before age 15. See questionnaire text for more details.

In two samples from Ghana (2014a and 2016a), answers to COHAB1STSTARTCMC were recorded for a small number of women who had been married only once. This does not appear to be a systematic change in the universe, and these data reflect the original PMA data, without any editing by IPUMS.

Comparability with IPUMS-DHS

COHAB1STSTARTCMC in IPUMS-PMA is similar to the variable MAR1STCMC in IPUMS-DHS. There may be differences in questionnaire text or the variable's universe; please see the Survey Text and Universe Tab of the IPUMS-DHS variable for more information.


  • Women aged 15 to 49 who have been married more than once.


  • Burkina Faso: 2014-2018, 2020-2022
  • Congo (Democratic Republic): 2014-2021
  • Cote d'Ivoire: 2017-2018, 2020-2022
  • Ethiopia: 2014-2019, 2021
  • Ghana: 2014-2017
  • India: 2016, 2020-2022
  • Indonesia: 2015-2016
  • Kenya: 2014-2021
  • Niger: 2015-2018, 2020, 2022-2023
  • Nigeria: 2014-2021
  • Uganda: 2014-2015, 2020-2022