WLS Codebooks and Flowcharts

Note: Codebooks contain frequency data from the private data release. For some variables, these differ from the frequencies in the public release. Variables that differ between the public and private versions include "(not available on public release)" as part of the variable description, or a note indicating the difference between the public and private versions.

Children

xkidsno - xfemkds  Number of children
xadptkd, xxadptno  Any adopted, step or foster children?
xagrkd1            Sibling's age at first child's birth
xdurmrb            Duration between marriage and first child
xpremrb            Have a premarital first birth?

There are up to 13 children recorded.
     xkdsex*         Sex of child
     xcmkdb*         Date of birth of child
     The suffix * can be 1 to 9, 0, a or b, where
        1 to 9 represents the first to the ninth child
        0 represents the tenth child
        a, b, c represent the 11th, the 12th and the 13th child, respectively

xsexlkd            Sex of last birth
xcmlkd             Date of birth of last child
xdurk12 - xdurkbc  Number of months between child and next child
xdurk1l            Number of months between first and last birth

xkidsno: Number of children ever had.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3394 3256 6650
-2 107 74 181
0 No children 110 121 231
1 One child 121 105 226
2 Two children 281 283 564
3 Three children 214 233 447
4 - 13 Four to thirteen children 210 269 479
13 13 0 1 1
Note: Prior to 8/06, this variable was labeld as "Sib-respondent's
Number of Biological or Natural Children."

Only females have data in variables XADPTKD-XWYNHAL because the
detailed child information (q79-q82) was not asked for males.

Before using these variables, see Appendix C - COR690 and
COR690a for important information regarding marriage dates,
fertility rosters, biological and non-biological children,
and work history sections for ever-married women.

xmalkds: Number of male children.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3393 3257 6650
-2 1044 195 1239
0 no male children 0 166 166
1 one 0 309 309
2 0 258 258
3 0 101 101
4 0 31 31
5 0 14 14
6 0 8 8
7 0 1 1
8 8 0 1 1
Note: For the five people who had more than 10 children, this
variable gives the number of males among the first 10
children. This is comparable to the 1975 data.

xfemkds: Number of female children.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3393 3257 6650
-2 1044 195 1239
0 no female children 0 168 168
1 one 0 346 346
2 0 231 231
3 0 87 87
4 0 32 32
5 0 16 16
6 0 6 6
7 0 2 2
8 8 0 1 1
Note: For the five people who had more than 10 children, this
variable gives the number of females among the first 10
children. This is comparable to the 1975 data.

xadptkd: Do you have any adopted, step or foster children?

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 80
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3256 6649
-2 1044 0 1044
0 NO 0 1047 1047
1 YES 0 38 38
Note: This question was asked in 1977 for all women with
children. In 1975, it was ascertained only in cases where
sib-respondent mentioned freely that some of the children
were adopted, step or foster children.

"No" includes never married women and women with no
children to retain comparability with 1975 data.

Before using these variables, see Appendix C - COR690 and
COR690a for important information regarding marriage dates,
fertility rosters, biological and non-biological children,
and work history sections for ever-married women.

xxadptno: How many adopted, step or foster children does sibling respondent have?

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78a, 79, 80
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3256 6649
-2 1044 72 1116
0 None 0 976 976
1 One 0 20 20
2 Two 0 16 16
3 Three 0 1 1
Note: The sum of XXADPTNO and XKIDSNO equals the response to Q78a
(How many children did sib-respondent ever have?)

Before using these variables, see Appendix C - COR690 and
COR690a for important information regarding marriage dates,
fertility rosters, biological and non-biological children,
and work history sections for ever-married women.

xagrkd1: Sibling respondent's age at the birth of the first child.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79, 93
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3393 3257 6650
-2 1044 195 1239
157 - 381 Years and fraction of years 0 889 889
Note: Implied decimal between second and third digits (e.g. 15.0).

xdurmrb: Number of months between sibling respondent's first marriage and birth of the first child.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 61a, 61b, 64a1, 72, 72a, 75a1, 78, 78b, 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3393 3258 6651
-2 1044 195 1239
0 - 8 0 194 194
9 - 12 0 197 197
13 - 21 0 184 184
22 - 39 0 177 177
40 - 194 0 136 136

xpremrb: Did sibling respondent have a premarital first birth?

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 61a, 61b, 64a1, 72, 72a, 75a1, 78, 78b, 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3393 3258 6651
-2 1044 195 1239
0 NO 0 859 859
1 YES 0 29 29
Note: All sib-respondents whose first birth occurred during the
same month as the first marriage were scored "1" on this
variable. Although this looks low, this is the number with
a premarital birth, not a premarital conception.

xkdsex1: Sex of first child.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3257 6650
-2 1044 195 1239
1 MALE 0 444 444
2 FEMALE 0 445 445

xcmkdb1: Date of birth of first child. Year on public release, century months on private release.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3257 6650
-2 1044 195 1239
455 - 673 0 177 177
674 - 723 0 178 178
724 - 771 0 180 180
772 - 829 0 177 177
830 - 925 0 177 177
Note: Last 2 digits of year times 12 plus 1 = January of year
used in the equation (e.g. 38 x 12 + 1 = 457 = January,
1938). See Appendix A - COR607 for Conversion into century months.

Year of birth (bottom-coded at 1950 and top-coded at 1974) on public release.

xkdsex2: Sex of second child.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3256 6649
-2 1044 301 1345
1 MALE 0 400 400
2 FEMALE 0 384 384

xcmkdb2: Date of birth of second child. Year on public release, century months on private release.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3256 6649
-2 1044 301 1345
483 - 926 CENTURY MONTHS 0 784 784
Note: Last 2 digits of year times 12 plus 1 = January of year
used in the equation (e.g. 38 x 12 + 1 = 457 = January,
1938). See Appendix A - COR607 for Conversion into century months.

Year of birth (bottom-coded at 1953 and top-coded at 1976) on public release.

xkdsex3: Sex of third child.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 584 1628
1 MALE 0 271 271
2 FEMALE 0 231 231

xcmkdb3: Date of birth of third child. Year on public release, century months on private release.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 584 1628
526 - 924 CENTURY MONTHS 0 502 502
Note: Last 2 digits of year times 12 plus 1 = January of year
used in the equation (e.g. 38 x 12 + 1 = 457 = January,
1938). See Appendix A - COR607 for Conversion into century months.

Year of birth (bottom-coded at 1956 and top-coded at 1975) on public release.

xkdsex4: Sex of fourth child.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 817 1861
1 MALE 0 136 136
2 FEMALE 0 133 133

xcmkdb4: Date of birth of fourth child. Year on public release, century months on private release.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 817 1861
615 - 924 CENTURY MONTHS 0 269 269
Note: Last 2 digits of year times 12 plus 1 = January of year
used in the equation (e.g. 38 x 12 + 1 = 457 = January,
1938). See Appendix A - COR607 for Conversion into century months.

Year of birth (bottom-coded at 1958 and top-coded at 1971) on public release.

xkdsex5: Sex of fifth child.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 944 1988
1 MALE 0 67 67
2 FEMALE 0 75 75

xcmkdb5: Date of birth of fifth child. Year on public release, century months on private release.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 944 1988
628 - 918 CENTURY MONTHS 0 142 142
Note: Last 2 digits of year times 12 plus 1 = January of year
used in the equation (e.g. 38 x 12 + 1 = 457 = January,
1938). See Appendix A - COR607 for Conversion into century months.

Year of birth (1952-1960 collapsed into 1958, 1961-1965 collapsed into 1963, 1966-70 collapsed into 1967 and 1971-1976 collapsed to 1973) on public release.

xkdsex6: Sex of sixth child.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 1023 2067
1 MALE 0 36 36
2 FEMALE 0 27 27

xcmkdb6: Date of birth of sixth child. Year on public release, century months on private release.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 1023 2067
647 - 918 CENTURY MONTHS 0 63 63
Note: Last 2 digits of year times 12 plus 1 = January of year
used in the equation (e.g. 38 x 12 + 1 = 457 = January,
1938). See Appendix A - COR607 for Conversion into century months.

Year of birth (1953-1964 collapsed into 1961 and 1965-1976 collapsed into 1968) on public release.

xkdsex7: Sex of seventh child.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 1052 2096
1 MALE 0 13 13
2 FEMALE 0 21 21

xcmkdb7: Date of birth of seventh child. Year on public release, century months on private release.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 1052 2096
650 - 910 CENTURY MONTHS 0 34 34
Note: Last 2 digits of year times 12 plus 1 = January of year
used in the equation (e.g. 38 x 12 + 1 = 457 = January,
1938). See Appendix A - COR607 for Conversion into century months.

Year of birth (1954-1965 collapsed into 1963 and 1966-1975 collapsed into 1970) on public release.

xkdsex8: Sex of eighth child.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 1066 2110
1 MALE 0 7 7
2 FEMALE 0 13 13

xcmkdb8: Date of birth of eighth child. Year on public release, century months on private release.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 1066 2110
678 - 892 CENTURY MONTHS 0 20 20
Note: Last 2 digits of year times 12 plus 1 = January of year
used in the equation (e.g. 38 x 12 + 1 = 457 = January,
1938). See Appendix A - COR607 for Conversion into century months.

Year of birth (1956-1965 collapsed into 1962 and 1967-1974 collapsed into 1970) on public release.

xkdsex9: Sex of ninth child.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 1074 2118
1 MALE 0 7 7
2 FEMALE 0 5 5

xcmkdb9: Date of birth of ninth child. Year on public release, century months on private release.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 1074 2118
699 - 904 CENTURY MONTHS 0 12 12
Note: Last 2 digits of year times 12 plus 1 = January of year
used in the equation (e.g. 38 x 12 + 1 = 457 = January,
1938). See Appendix A - COR607 for Conversion into century months.

Year of birth (1968-1975 collapsed into 1966) on public release.

xkdsex0: Sex of tenth child.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 1081 2125
1 MALE 0 3 3
2 FEMALE 0 2 2

xcmkdb0: Date of birth of tenth child. Year on public release, century months on private release.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3255 6648
-2 1044 1081 2125
727 - 827 CENTURY MONTHS 0 5 5
Note: Last 2 digits of year times 12 plus 1 = January of year
used in the equation (e.g. 38 x 12 + 1 = 457 = January,
1938). See Appendix A - COR607 for Conversion into century months.

Year of birth (1960-1968 collapsed into 1966) on public release.

xkdsexa: Sex of eleventh child.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Added 2/2014     
*NOT AVAILABLE ON PUBLIC RELEASE*

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3394 3256 6650
-2 1043 1080 2123
1 MALE 0 3 3
2 FEMALE 0 2 2

xcmkdba: Date of birth of eleventh child. Year on public release, century months on private release.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Added 2/2014     
*NOT AVAILABLE ON PUBLIC RELEASE*

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3394 3256 6650
-2 1043 1080 2123
738 0 1 1
810 0 1 1
820 0 1 1
836 0 1 1
894 0 1 1
Note: Last 2 digits of year times 12 plus 1 = January of year
used in the equation (e.g. 38 x 12 + 1 = 457 = January,
1938). See Appendix A - COR607 for Conversion into century months.

xkdsexb: Sex of twelfth child.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Added 2/2014     
*NOT AVAILABLE ON PUBLIC RELEASE*

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3394 3256 6650
-2 1043 1082 2125
1 MALE 0 1 1
2 FEMALE 0 2 2

xcmkdbb: Date of birth of twelfth child. Year on public release, century months on private release.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Added 2/2014     
*NOT AVAILABLE ON PUBLIC RELEASE*

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3394 3256 6650
-2 1043 1082 2125
762 0 1 1
824 0 1 1
860 0 1 1
Note: Last 2 digits of year times 12 plus 1 = January of year
used in the equation (e.g. 38 x 12 + 1 = 457 = January,
1938). See Appendix A - COR607 for Conversion into century months.

xkdsexc: Sex of thirteenth child.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Added 2/2014     
*NOT AVAILABLE ON PUBLIC RELEASE*

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3394 3256 6650
-2 1043 1084 2127
1 MALE 0 1 1

xcmkdbc: Date of birth of thirteenth child. Year on public release, century months on private release.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 79
Revisions: Added 2/2014     
*NOT AVAILABLE ON PUBLIC RELEASE*

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3394 3256 6650
-2 1043 1084 2127
897 0 1 1
Note: Last 2 digits of year times 12 plus 1 = January of year
used in the equation (e.g. 38 x 12 + 1 = 457 = January,
1938). See Appendix A - COR607 for Conversion into century months.

xsexlkd: Sex of last birth.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Updated 3/97, 9/99, 2/2014     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3257 6650
-2 1044 195 1239
1 MALE 0 449 449
2 FEMALE 0 440 440
Note: Prior to release 13.02, for the five people who had more than 10
children, this variable is the sex of the tenth child. From release
13.02 on, this variable is the sex of the last child reported.

xcmlkd: Date of birth of last child. Year on public release, century months on private release.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Updated 3/97, 9/99, 2/2014     

Frequencies
Value Label Male Female Total
-3 NOT ASCERTAINED OR NONSAMPLE 3393 3257 6650
-2 1044 195 1239
455 - 926 CENTURY MONTHS 0 889 889
Note: Prior to release 13.02, for the five people who had more than 10
children, this variable is the century month of birth of the tenth
child. From release 13.02 on, this variable is the century month of
birth of the last child reported.

Last 2 digits of year times 12 plus 1 = January of year
used in the equation (e.g. 38 x 12 + 1 = 457 = January,
1938). See Appendix A - COR607 for Conversion into century months.

Year of birth (bottom-coded at 1957 and top-coded at 1976) on public release.

xdurk12: Number of months between first and second birth.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3393 3257 6650
-2 1044 300 1344
0 - 15 0 178 178
16 - 22 0 179 179
23 - 31 0 163 163
32 - 45 0 161 161
46 - 166 0 103 103

xdurk23: Number of months between second and third birth.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3393 3256 6649
-2 1044 583 1627
0 - 16 0 100 100
17 - 23 0 105 105
24 - 33 0 104 104
34 - 50 0 101 101
51 - 241 0 92 92

xdurk34: Number of months between third and fourth birth.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Updated 3/97, 9/99     

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3393 3256 6649
-2 1044 816 1860
0 - 17 0 66 66
18 - 24 0 56 56
25 - 36 0 53 53
37 - 60 0 53 53
61 - 187 0 41 41

xdurk45: Number of months between fourth and fifth birth.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3393 3256 6649
-2 1044 943 1987
0 - 15 0 29 29
16 - 22 0 30 30
23 - 35 0 30 30
36 - 52 0 29 29
53 - 162 0 24 24

xdurk56: Number of months between fifth and sixth birth.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3393 3256 6649
-2 1044 1022 2066
0 - 17 0 12 12
18 - 23 0 12 12
25 - 30 0 14 14
31 - 46 0 12 12
47 - 149 0 13 13

xdurk67: Number of months between sixth and seventh birth.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3393 3256 6649
-2 1044 1051 2095
2 - 15 0 6 6
16 - 18 0 8 8
19 - 23 0 8 8
26 - 38 0 6 6
42 - 78 0 6 6

xdurk78: Number of months between seventh and eighth birth.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3393 3256 6649
-2 1044 1065 2109
0 0 1 1
8 0 1 1
10 0 1 1
11 0 1 1
12 0 1 1
14 0 2 2
16 0 1 1
18 0 2 2
19 0 1 1
20 0 2 2
28 0 1 1
33 0 1 1
34 0 1 1
35 0 1 1
38 0 1 1
43 0 1 1
72 0 1 1

xdurk89: Number of months between eighth and ninth birth.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3393 3256 6649
-2 1044 1073 2117
11 0 1 1
12 0 1 1
16 0 1 1
20 0 1 1
21 0 2 2
23 0 2 2
28 0 1 1
36 0 1 1
40 0 1 1
46 0 1 1

xdurk90: Number of months between ninth and tenth birth.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Updated 3/97     

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3393 3256 6649
-2 1044 1080 2124
15 0 1 1
16 0 1 1
17 0 1 1
23 0 1 1
28 0 1 1

xdurk0a: Number of months between tenth and eleventh birth.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Added 2/2014     
*NOT AVAILABLE ON PUBLIC RELEASE*

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3394 3256 6650
-2 1043 1080 2123
11 0 1 1
16 0 1 1
25 0 1 1
28 0 1 1
67 0 1 1

xdurkab: Number of months between eleventh and twelfth birth.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Added 2/2014     
*NOT AVAILABLE ON PUBLIC RELEASE*

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3394 3256 6650
-2 1043 1082 2125
14 0 1 1
24 0 1 1
40 0 1 1

xdurkbc: Number of months between twelfth and thirteenth birth.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Added 2/2014     
*NOT AVAILABLE ON PUBLIC RELEASE*

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3394 3256 6650
-2 1043 1084 2127
37 0 1 1

xdurk1l: Number of months between first and last birth.

Data source: Sibling Respondent      Collected in: 1977      Mode: phone
Source variables: 78, 78b, 79
Revisions: Updated 3/97, 9/99, 2/2014     

Frequencies
Value Label Male Female Total
-3 DON'T KNOW, NOT ASCERTAINED OR NONSAMPLE 3393 3257 6650
-2 1044 300 1344
0 - 33 0 162 162
34 - 54 0 162 162
55 - 79 0 164 164
80 - 119 0 156 156
120 - 277 0 140 140
Note: Prior to release 13.02, for the five people who had more than 10
children, this variable is the length of time between the first birth
and the tenth child. From release 13.02 on, this variable is the
length of time between the first birth and the last birth. This is
comparable to the 1975 data.

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