IFSS_AGEFSTLB: Age at first live birth

View as PDF | Download Stata source code | Download EXCEL File

Summary for Variable Group: Pregnancy and birth history

This variable group provides information about the respondent's total number of births, live births, miscarriages or stillbirths, and pregnancies. It also contains information on the century month of her first and most recent live births, her age at first birth, age at menarche, menstrual status, current pregnancy status, and whether she has ever given a baby up for adoption. More complete information on pregnancies and births is located in the pregnancy interval file.


IFSS_AGEFSTLB

Age at first live birth

Availability

2002 NSFG
1995 NSFG
1988 NSFG
1982 NSFG
1976 NSFG: Interval File
1973 NSFG
1970 NFS
1965 NFS
1960 GAF
1955 GAF

Source Variables

Source Questions

PRGOUTCOME Computed 2002 NSFG
CMPRGEND Computed 2002 NSFG
NBRNLV BC-2 1995 NSFG
BABDOB BD-6 1995 NSFG
NUMBIRTH Computed 1988 NSFG
B14MO B-14 1988 NSFG
BP1920B B-19 1982 NSFG
B22A B-22 1982 NSFG
BPREC4 Computed 1976 NSFG: Interval File
BPREC2 Computed 1976 NSFG: Interval File
LB1_DTENDED Q.19A 1973 NSFG
PREG1_TERM CM.106 1970 NFS
PREG1_OUT Computed 1970 NFS
PREG1_TERM Computed 1965 NFS
PREG1_OUT Computed 1965 NFS
CH1_SEX 14a 1960 GAF
CH1_DOB 14b 1960 GAF
PREG1_YREND 10/14 1955 GAF
PREG1_OUT 10/14 1955 GAF
PREG1_MEND 10/14 1955 GAF

Description

This variable provides the age (in completed years) of the respondent at her first live birth, including babies who died shortly after birth.

General Comparability Notes

Summary: IFSS_AGEFSTLB is highly comparable across all surveys.

In all years this variable is computed using the century month for the end date of the respondent’s first pregnancy, recorded in IFSS_CMFSTLB, and the respondent's century month of birth, recorded in IFSS_CMBIRTH, according to the formula:

IFSS_AGEFSTLB = trunc[(IFSS_CMFSTLB – IFSS_CMBIRTH)/12].

That is, the respondent's age in years is calculated by calculating the number of months between her birth and her first live birth, dividing by 12, and then rounding to produce the number of completed years.

In all years, pregnancy outcome and end date were asked for every live birth, as was the respondent's date of birth, so the universes are identical across surveys.

See also:
IFSS_CHALIVE
IFSS_CMFSTLB
IFSS_CMFSTPRG
IFSS_CMLASTLB
IFSS_NUMPREGS
IFSS_PARITY
IFSS_MISSTILL
IFSS_NLVBRTH

Imputation Flag Exists

Imputation Flag Values
-1 Illogical value
0 Not imputed
1 Imputed in original study
2 Logically imputed
3 Month imputed (Original file edit)
4 Age known, month imputed
5 Originally imputed as June, recoded to random month
6 Month imputed
7 Multiple regression imputed: Not ascertained
8 Multiple regression imputed: Refused
9 Multiple regression imputed: Don't know
10 Midpoint of a given range
11 Answer comes from a follow-up question
12 Midpoint of a range given as a follow-up
13 Answer is rounded up
14 Answer is rounded down
15 Reported months and weeks, weeks<=4
16 Reported months=trunc(weeks/4.35)
17 Reported months=weeks & weeks>4
18 Reported months!=trunc(weeks/4.35), months!=weeks, weeks>4
19 Months coded NA/RF/DK
20 Weeks coded NA/RF/DK
21 Impossible to determine which method used last

Return to variable list

Inter-university Consortium for Political and Social Research       Inter-university Consortium for Political and Social Research       Population Studies Center
© 2013 The Regents of the University of Michigan