Documentation for Variables Used in The Bell Curve Regression Analyses

Files are saved as Macintosh text files with labels, tab indicating end of field, and CR indicating end of line.
The data files are contained in self‑extracting archives. Double‑click on the icon to extract the files.
 “CY”: Calendar year. “SY”: Survey year. For numeric binary variables, 1=yes, 0=no.
Means, standard deviations, and frequency distributions are provided for purposes of checking that the file has been accurately transferred. These statistics are computed without sample weights; hence standardized variables, which were created using sample weights, do not show a mean of 0 and an SD of 1. 
Note when replicating analyses: 
•	The analyses shown in Chapters 5–12 use sample weights applied to the entire white sample. The parallel analyses reported in Appendix 4 do not use sample weights, and are based on the white cross-sectional sample. 
•	The analyses shown in graphs in Chapter 15 and reported in Appendix 6 are all based on the entire white, black, and Latino samples, applying sample weights.
•	The analyses reported in Appendix 6 using the HOME index or any of the child assessment indexes include TestYr and the appropriate age category (e.g., PPVTAge for the analysis of PPVT6Bot) as independent variables.  
If you have problems or questions, call Charles Murray at (301) 834-7425, fax the information to (202) 862-7177, or use e-mail address chasmurray@aol.com.

NATION.TXT
12,686 cases, 50 variables
This file includes variables scored for all NLSY subjects, one line per subject.
Variables in the file are in the order listed below. The first 11 (through EdSamples) are the most commonly used variables. From then on, the variables are listed in alphabetical order. 
Core variables:
ID	ID number. 
AFQT80	AFQT score using the 1980 scoring system, excluding invalid scores (R6148, code 67). Not corrected for skew.
Valid cases=11878    Mean=65.29    Std. Dev.=22.13
AFQT89	AFQT score using the 1989 scoring system. Not corrected for skew. See discussion of scoring procedure on p. 570 of The Bell Curve.
Valid cases=11878    Mean=190.26    Std. Dev.=37.95
 zAFQT89	Standard score for the AFQT 1989 scoring system corrected for skew. Assigns z‑scores corresponding to the value of AFQT89 centile in a normal distribution, cutting off scores at 3 SDs from the mean. This is the variable used in all the logistic analyses reported in The Bell Curve. 
Valid cases=11878    Mean=‑.26    Std. Dev.=1.01
zIQ*Yr89	Age‑equated AFQT standard scores corrected for skew. The reference group is the cohort of subjects born in a given subject’s birth year. 
Valid cases=11878    Mean=‑.27    Std. Dev.=1.01
Wgt90	Sample weight for SY90.
Valid cases=12686    Mean=2645.39    Std. Dev.=2463.79
WASVAB	The sample weight assigned in 1980 to all those who took the AFQT.
Valid cases=11878    Mean=2818.25    Std. Dev.=2282.71
zAge	Standard score for age of the respondent.
Valid cases=12686    Mean=.05    Std. Dev.=.99
zSES	The SES index expressed as a standardized score. Construction of the SES index is described in Appendix 2, pp. 573–575. 
Valid cases=11876    Mean=‑.36    Std. Dev.=1.06
Race4	Subject’s race. Race for Black and Hisp is assigned according to the NLSY’s cohort categorization (variable R2147).  The remaining cohort identified by the NLSY as non‑black and non‑Latino on variable R2147 is split into Other (using variable R96, includes persons of self‑identified American Indian, Asian, and Pacific descent), and White, consisting of the rest. 
Black	3174	
Hisp	2002	
Other	569	
White	6941	
Total	12686	
EdSamples	Identifies the two homogeneous‑education samples used in Part II. “College” indicates a person with a FinDegree of BA or BS and 16 years of education as of SY90. “HS” indicates FinDegree consisting of HS and 12 years of education as of SY90. 
College	1098	
HS	3645	
Total	4743	
Variables in alphabetical order:
1MoNoWk89	Identifies people who worked at least one week in 1989 but less than 48. Excludes people who reported not working because of school in SY89 or SY90. 
0	6107	
1	2632	
Total	8739	
1MoOLF89	Identifies people who were out of the labor force for at least 4 weeks in 1989. Excludes people who reported not working because of school in SY89 or SY90.
0	6636	
1	3005	
Total	9641	
1MoUnemp89 	Identifies people who were unemployed for at least 4 weeks in 1989. Excludes people who reported not working because of school in SY89 or SY90.
0	8621	
1	1358	
Total	9979	
30+Samp	Identifies those whose age at the 1990 interview was ≥30. 
0	5850	
1	4586	
Total	10436	
Adult14Bio	Original (biological or adoptive) parents living with respondent at age 14.
Mom	3181	
Mom/Pop	8570	
Neither	534	
Pop	382	
Total	12667	
Adult14Sum	Summary of parental configuration at age 14. Based only on formal marital status (live‑in boyfriends or girlfriends don’t count). Alternatives are “2Orig” (both original parents), “Orig/Step (either remarried original parent), “UnmarMom” (never married mother or a divorced, still unmarried mother), and “Other” (includes arrangements in which child was living with original father, no stepmother, as well as all arrangements in which neither original parent was present). 
2 Orig	8570	
Orig/Step	1032	
Other	725	
UnmarMom	2340	
Total	12667	
AgeMarry	Age at first marriage.
Valid cases=6962    Mean=22.412    Std. Dev.= 3.489
AllvBA+	Binary variable distinguishing all those who had a bachelor’s degree or higher as of SY90 from those who had less than a bachelor’s degree.
0	8554	
1	1745	
Total	10299	
BA AttainSamp 	Used to identify persons who were still enrolled as college undergraduates as of 1 May 1990. “Eligible” means the subject could be used for the analysis using AllvBA+ as the dependent variable. 
Eligible	12230	
InSchl/NoD	456	
Total	12686	
BornWhere	Country of birth. 0=US, 1=elsewhere. 
0	11811	
1	874	
Total	12685	
Div5Yrs	Did the marriage end in divorce during the first five years? Limited to marriages that occurred prior to 1986. 
0	4005	
1	971	
Total	4976
DOB 	Birthdate, expressed in years.
Valid cases= 12686    Mean=60.84    Std. Dev.=2.26
Emp<>568	Subject was not in the military, or not working because unable to work or in school in either SY89 or SY90 (R30743, 34010).
1	9639	
Total	9639	
Emp<>Schl	Subject did not respond “not working because in school” in either SY89 or SY90 (R30743, 34010). 
1	10078	
Total	10078	
EverWed	Had the subject ever been married as of SY90? 
0	3345	
1	6971	
Total	10316	
FinDegree	Assignment of highest degree ever attained by SY90, discarding cases in which the reported years of education were markedly incommensurate with the reported degree. See discussion in Appendix 2, pp. 575–576. LTHS: Less Than High School; ProfDeg: PhD, law degree, medical degree; Assoc: Associate’s Degree. HS indicates a high school diploma achieved by the normal route, excluding all GEDs.
Assoc	608	
BA	1422	
GED	1151	
HS	5062	
LTHS	1733	
MA	243	
ProfDeg	80	
Total	10299	
GEDvHSGrad 	Binary variable distinguishing GEDs from all who got a HS diploma through the normal route (including those who went on to further education). Persons with neither a GED or HS diploma are not coded. 
GED	1151	
HSGrad	7415	
Total	8566	
Health89	“Prevent”: subject prevented from working in CY89. “Limit”: subject limited in amount or type of work in CY89. “None”: no health limitations on work in CY89. 
Limit	445	
None	9882	
Prevent	278	
Total	10605	
HiIQOcc	Classified 1 if subject is a civilian and his/her occupation is one of the high IQ occupations as defined in chapter 2, 0 if the person reports some other occupation.
0	8546	
1	403	
Total	8949	
IntAge90	Age at time of 1990 interview, in whole years.
25	285	
26	1382	
27	1405	
28	1420	
29	1358	
30	1385	
31	1197	
32	1212	
33	792	
Total	10436	
Jail	Those ever interviewed in jail, excluding those who were not interviewed in jail but are not part of the 1990 sample. Note: the other measure of crime in chapter 11, those in the top decile of self-reported crime as of the 1979 interview, was based on the white male distribution and computed only for white males (because of known large ethnic differences in self-report behavior) and is not included in this data file. 
0	10052	
1	430	
Total	10482	
KInc89 	Total net family income in CY89 expressed in 1990 dollars, using CPI.
Valid cases=8688    Mean=33866.27    Std. Dev.=26994.14
KWage89	Total salary and wages for the respondent in CY1989 expressed in 1990 dollars.
Valid cases=10200    Mean=16320.27    Std. Dev.=16308.31
LTHSvAll	Binary variable distinguishing those without either a HS diploma or GED from all others with a GED, HS diploma, or more advanced degree. 
AllOther	8566	
LTHS	1733	
Total	10299	
LTHSvGED	Binary variable distinguishing those without either a HS diploma or GED from all others with a GED. Those who got their HS diploma through the normal route are not coded. 
GED	1151	
LTHS	1733	
Total	2884	
LTHSvHSGrad 	Binary variable distinguishing those without a HS diploma from all who got a HS diploma through the normal route (including those who went on to further education). Persons with a GED are not coded.
HSGrad	7415	
LTHS	1733	
Total	9148	
MarDate1	Date of first marriage, in years.
Valid cases=6962    Mean=83.208    Std. Dev.=3.861
MCV Index	The Middle Class Values Index, scored 1 and 0 as described in chapter 12. Single people and men in school or unable to work in 1989 or 1990 who otherwise would have scored 1 are treated as missing. 
0	5420	
1	2939	
Total	8359	
Occ90Type	Type of occupation in 1990, using the 1970 census occupational categories. 
Clerical	1698
Craft	1061	
Farm	96	
Labor	530	
Mgr	989	
NA	1459	
Operatv	929	
Prof/Tech	1417	
Sales	415	
Service	1444	
Transpt	356	
Total	10394	
Pov89	Subject’s family was below the poverty line in calendar year 1989
0	7316	
1	1372	
Total	8688	
RelAtt	Attendance at religious services. “Wkly+” indicates more than once per week. 
1/mo	1175	
1/wk	2728	
2‑3/mo	1537	
Infreq	3501	
None	2543	
Wkly+	1185	
Total	12669
Sample	The original samples for the NLSY.
Military	1280	
Supplement	5295	
XSection	6111	
Total	12686	
Sex	Gender. 
Female	6283	
Male	6403	
Total	12686	
UnempSamp	Denotes civilians who were in the labor force throughout 1989 and did not respond “not working because in school” in either SY89 or SY90 (R30743, 34010).
1	5959	
Total	5959	
Wed90	Marital status as of SY90. Modification relies on the Fertility file characterization, but uses the cross‑sectional information to identify separated and widowed persons. 
Married	5367	
NevMar	3345	
Sep/Div	1523	
Widow	45	
Total	10280	
WedBy30	Was the respondent married prior to the age of 30?
1 Yes	3268	
2 No	1261	
Total	4529
Work89	Weeks worked in CY89.
Valid cases=10436    Mean=38.53    Std. Dev.=19.49
YrRndWrkr	Work89=52, with KWage89 greater than 0.
1	5217	
Total	5217	
zEd90	Standard score for the years of education as of SY90. 
Valid cases=10358    Mean=‑.16    Std. Dev.=1.02 

WOMEN.TXT
6,283 cases, 28 variables

Variables scored for all women in the NLSY (one case per subject).
Core variables: 
ID	ID number. 
zAFQT89	Standard score for the AFQT, 1989 scoring system, corrected for skew. See description in NATION.TXT documentation.
Valid cases=5927    Mean=‑.268    Std. Dev.=.958
zIQ*Yr89	Age‑equated AFQT standard scores, corrected for skew. The reference group is the cohort of subjects born in a given subject’s birth year.
Valid cases= 5927    Mean=‑.278    Std. Dev.=.953
Wgt90	Sample weight for SY90. 
Valid cases=6283    Mean=2624.257    Std. Dev.=2369.636
WASVAB	The sample weight assigned in 1980 to all those who took the AFQT.
Valid cases=5927    Mean=2778.969    Std. Dev.=2260.305
zAge	Standard score for age of the respondent. 
Valid cases=6283    Mean=.055    Std. Dev.=.981
zSES	The SES index expressed as a standardized score. Construction of the SES index is described in Appendix 2. 
Valid cases=5925    Mean=‑.368    Std. Dev.=1.070
Race4	Subject’s race. See description in NATION.TXT documentation.
Black	1561	
Hisp	1002	
Other	292	
White	3428	
Total	6283 
EdSamples	Identifies the two homogeneous‑education samples used in Part II. See description in NATION.TXT documentation.
College	577	
HS	1831	
Total	2408

Variables in alphabetical order:
30+Samp	Identifies those whose age at the 1990 interview was ≥30. 
0	2906	
1	2418	
Total	5324
ADCBin	Did the woman ever receive AFDC? Coded “yes” for all women reporting at least one year of AFDC recipiency. Coded “no” for women without children and with no reported AFDC recipiency; and for women with children who had no missing AFDC data  from SY79–SY90, a child born after 1977, and no reported AFDC recipiency.
1 Yes	1368	
2 No	3562	
Total	4930	
ADCEarly	Had the woman received AFDC by the end of the CY following birth of the child? 
0	2130	
1	673	
Total	2803	
Adult14Bio	Original parents (biological or adoptive) living with respondent at age 14.		
Mom	1609	
Mom/Pop	4229	
Neither	273	
Pop	163	
Total	6274	
Adult14Sum	Summary of parental configuration at age 14. See description in NATION.TXT documentation.
2 Orig	4229	
Orig/Step	514	
Other	352	
UnmarMom	1179	
Total	6274	
Age1stBirth	Mother’s age at first birth, in years.
Valid cases=3686    Mean=21.736    Std. Dev.=3.973
BStatus	Legitimacy status of the first‑born child. 
Illegit	1288	
Legit	2343	
Total	3631	
ChronBin	Contrasts chronic welfare recipients with women with children who had no welfare experience. Chronic welfare recipiency (=1) is defined as five or more years of welfare recipiency from CY78–CY89. The comparison group (=0) is women whose first child was born after 1977 but prior to 1986, with complete AFDC data but 0 years of welfare. 
0	1211	
1	572	
Total	1783	
DOB 	Birthdate, expressed in years. 
Valid cases=6283    Mean=60.820    Std. Dev.=2.243
DOBKid	Date of birth of the first child. 
Valid cases=6283    Mean=82.505    Std. Dev.=4.178
IllegMom	Mother has given birth to a child out of wedlock (0 scores include women with no children). 
0	3981	
1	1288	
Total	5269	
IntAge90	Age at time of 1990 interview, in whole years.
25	122	
26	693	
27	696	
28	688	
29	707	
30	712	
31	623	
32	661	
33	422	
Total	5324	
MarDate1	Date of first marriage, in years. 
Valid cases=3822    Mean=82.498    Std. Dev.=3.968
NKids	Number of children as of SY90.
Valid cases=5324    Mean=1.443    Std. Dev.=1.295
Pov1st3Yrs	First child lived in poverty throughout its first three years. 
0	1142	
1	283	
Total	1425	
PreBthPov	Was the woman in poverty in the CY before the birth of the first child? 
0	1970	
1	570	
Total	2540	
Sample	The original samples for the NLSY. 
Military	456	
Supplement	2719	
XSection	3108	
Total	6283
Wed90	Marital status as of SY90. Modification relies on the Fertility file characterization, but uses the cross‑sectional information to identify separated and widowed persons. 
Married	2880
NevMar	1432	
Sep/Div	893	
Widow	36	
Total	5241	
zEd90	Standard score for the years of education as of SY90. 
Valid cases=5276    Mean=‑.127    Std. Dev.=.995

CHILD1.TXT
8,513 cases, 26 variables

Variables scored for all NLSY children, representing one case per child for whom data were available through SY90.
Core Variables:
KidID	Child’s ID number
MomID	Mother’s ID number. 
zAFQT89	Standard score for the AFQT, 1989 scoring system, corrected for skew. See description in NATION.TXT documentation.
Valid cases=8041    Mean=‑.525    Std. Dev.=.939
zIQ*Yr89	Age‑equated AFQT standard scores, corrected for skew. The reference group is the cohort of subjects born in a given subject’s birth year. 
Valid cases=8041    Mean=‑.556    Std. Dev.=.920
KidWgt90	Child’s sample weight for SY90. 
Valid cases=5803    Mean=3559.027    Std. Dev.=2396.266
zAge	Standard score for age of the mother. 
Valid cases=8513    Mean=.184    Std. Dev.=.963
zSES	The SES index expressed as a standardized score (refers to the SES background of the mother). Construction of the SES index is described in Appendix 2. 
Valid cases=8037    Mean=‑.626    Std. Dev.=1.041
Race4	Mother’s race. See description in NATION.TXT documentation.
Black	2462	
Hisp	1575	
Other	430	
White	4046	
Total	8513
EdSamples	Identifies the two homogeneous‑education samples used in Part II. See description in NATION.TXT documentation.
College	404	
HS	2789	
Total	3193

Variables in alphabetical order:
30+ Sample	Mother was 30 or older as of SY1990. 
1	4066	
Total	4066	
 ADCEarly	Mother received AFDC by the end of the calendar year following birth of the child. 
0	4671	
1	1881	
Total	6552
	
ADCYr0	Mother received AFDC in the calendar year the child was born
0	5750	
1	1373	
Total	7123
ADCYr1	Mother received AFDC in the calendar year following the birth of the child.
0	5300	
1	1461	
Total	6761	
AgeBirth	Age of mother at birth, in years. 
Valid cases=8511    Mean=23.092    Std. Dev.=3.956
AgeMarry	Age at which the mother married, in years. 
Valid cases=6335    Mean=20.692    Std. Dev.=3.277
BStatus	Legitimacy status of the child. 
Illegit	2355	
Legit	5191	
Total	7546 
DOBKid	Child’s date of birth, in years. 
Valid cases=8511    Mean=83.616    Std. Dev.=4.077

EvFosOrRel	For children with complete residence data, was he/she ever listed as living in foster care or as living with nonparental relatives? 
0	8088	
1	361	
Total	8449
LBW	Low birth weight, defined as ≤88 ozs. Children under 88 ozs. whose weight was appropriate for gestational age were coded as missing. 
LBW	521	
Not LBW	7306	
Total	7827	
Pov1st3Yrs	Child lived in poverty throughout its first three years 
0	2228	
1	854	
Total	3082
PreBthPov	Mother in poverty in the calendar year prior to birth. 
0	4503	
1	1795	
Total	6298
PreNat1stTri	Mother received prenatal care in the first trimester. 
0	1666	
1	5989	
Total	7655	
Reside90	Custodial adults residing with the child in SY90. “Dead” refers to deceased children.
2 Pars	4507	
Adoptive	57	
Dead	101	
Foster	19	
Mom	2594	
Pop	204	
Relatives	138	
Total	7620
Sample	The original samples of the NLSY
Military	415	
Supplement	4245	
XSection	3853	
Total	8513	
SmokeBin	Mother smoked during pregnancy. 
No	5347	
Yes	2529	
Total	7876	
zEd90	Mother’s years of education as of SY90, expressed as a standard score based on the entire NLSY population. 
Valid cases=7622    Mean=‑.466    Std. Dev.=.926

CHILD2.TXT
17,040 cases, 40 variables 
Each case represents one child for one test year. A given child may therefore be represented in up to three cases. TY=test year.
Percentiles on the developmental and behavioral indicators all represent within‑gender percentiles.
Core variables:
KidID	Child’s ID number
MomID	Mother’s ID number. 
TestYr	Test year. 
86	4971	
88	6266	
90	5803	
Total	17040
zAFQT89	Standard score for the AFQT, 1989 scoring system, corrected for skew. See description in NATION.TXT documentation.
Valid cases=16294    Mean=‑.60    Std. Dev.=.93
zIQ*Yr89	Age‑equated AFQT standard scores, corrected for skew. The reference group is the cohort of subjects born in a given subject’s birth year. 
Valid cases=16294    Mean=‑.63    Std. Dev.=.91
KidWgt	Child’s sample weight for the TY in question. 
Valid cases=17040    Mean=3008.82    Std. Dev.=2270.10
zAge	Standard score for age of the mother. 
Valid cases=17040    Mean=.18    Std. Dev.=.96
zSES	The SES index expressed as a standardized score (refers to the SES background of the mother). Construction of the SES index is described in Appendix 2. 
Valid cases=16289    Mean=‑.69    Std. Dev.=1.03
Race4	Mother’s race. See description in NATION.TXT documentation.
Black	5493	
Hisp	3399	
Other	785	
White	7363	
Total	17040
EdSamples	Identifies the two homogeneous‑education samples used in Part II. See description in NATION.TXT documentation.
College	700	
HS	6283	
Total	6983	
Variables in alphabetical order:
AgeBirth 	Age of mother at birth, in years. 
Valid cases=17040    Mean=22.40    Std. Dev.=3.66
AgeCA	Age of child in months at child assessment. 
Valid cases=17040    Mean=68.09    Std. Dev.=44.49
AgeMA	Age of child in months at mother assessment. 
Valid cases=17040    Mean=68.09    Std. Dev.=44.49
BehProbBot	The worst decile in the BehProb index, based on BehProbZ for whites, ages 4‑11.
0	7866	
1	1003	
Total	8869
BehProbZ	Same‑sex std. score on the behavioral problems index. Uses national norms, mean=100, SD=15. This was used to create the “bottom decile” coding for the behavioral problems index reported in chapter 10, based on the worst decile for the white sample. Note: The racial discrepancies in this variable, based on the mother’s report of behavioral problems, were large, with black mothers reporting substantially lower levels of behavioral problems than other mothers. This is inconsistent with other data in the NLSY, and consistent with literature on comparable behavioral self‑reports suggesting that such differences represent inter‑ethnic differences in interpretation of the items rather than inter‑ethnic differences in behavior. We therefore elected to define the bottom decile on the basis of the white sample in chapter 10. In chapter 14, we applied the scoring based on the white decile to the other races as well, and inserted a caveat about interpretation.
Valid cases=9855    Mean=108.078    Std. Dev.=14.376
BPAgeCat	Behavioral problems index age categories, in years.
4‑7	5956	
8‑11	3558	
Total	9514
BStatus	Legitimacy status of child. 
Illegit	5416	
Legit	10961	
Total	16377
DevProbIndex 	Was the child in the worst decile on any of the four developmental indexes? (DiffBot, FriendBot, MoSocBot, BehProbBot) 
1 Yes	1747	
2 No	13178	
Total	14925
DiffBot	In the worst decile in the Difficulty index, for infants ages 12–23 mos.
0	1314	
1	185	
Total	1499	
Difficult%	Same‑sex percentile score on the Difficulty index, normed for age. 
Valid cases=1499    Mean=53.221    Std. Dev.=29.502
DOBKid	Child’s date of birth, in years. 
Valid cases=17040    Mean=82.95    Std. Dev.=3.73
Friend%	Same‑sex percentile score on the Friendliness index, normed for age. 
Valid cases=1510    Mean=46.698    Std. Dev.=29.297
FriendBot	In the worst decile in the Friendly index, for infants ages 12–23 mos. 
0	1304	
1	206	
Total	1510
Home%	Percentile score on the HOME scale. Normed for NLSY children (no national norms available). 
Valid cases=16086    Mean=45.90    Std. Dev.=29.42
HomeAgeCat	HOME index age categories, in years.
0‑2	4777	
3‑5	4860	
6+	7403	
Total	17040
HomeBot	In the worst decile on the HOME scale. 
0	13293	
1	2793	
Total	16086	
LBW	Low birth weight, defined as ≤88 ozs. Children under 88 ozs. whose weight was appropriate for gestational age were coded as missing. 
LBW	1051	
Not LBW	14981	
Total	16032
MoSoc%	Same‑sex percentile score on motor & social development index, normed for age. 
Valid cases=5873    Mean=51.075    Std. Dev.=28.535
MoSocBot	In the worst decile on the Motor & Social Development index. 
0	5371	
1	502	
Total	5873
MSAgeCat 	Motor & social development age categories, in months.
0‑23	3153	
24‑47	3299	
Total	6452	
Pov1st3Yrs	Child lived in poverty throughout his/her first three years 
0	5065	
1	2097	
Total	7162	.
PPVT	PPVT standard score, based on national norms, expressed in IQ points. Children with scores lower than 40 (4 SDs below the mean) were assigned a score of 40.
Valid cases=6069    Mean=86.039    Std. Dev.=20.895
PPVT6 	PPVT scores for children ages 6 and older at the time of the test, and for whom the mother has an AFQT score.
Valid cases=2651    Mean=87.863    Std. Dev.=17.324
PPTV6Bot	In the worst decile on the PPVT, based on national norms, limited to children ages 6 and older at the time they took the test. 
1 Yes	902	
2 No	1861	
Total	2763
PPVTAge	Age in months at time of PPVT assessment. 
Valid cases=15289    Mean=73.61    Std. Dev.=44.02
PreBthPov	Mother in poverty in the calendar year prior to birth. 	
0	8803	
1	3893	
Total	12696	
PreTYADC 	Child’s mother was receiving welfare in the calendar year prior to TY. 
0	13265	
1	3721	
Total	16986	
PreTYPov	Child was below the poverty line in the calendar year prior to TY. 
0	9807	
1	5001	
Total	14808	
Sample	The original NLSY samples.		
Military	55	
Supplement	8495	
XSection	8490	
Total	17040
TempAgeCat	Temperament age categories, for Difficulty & Friendly scales, in months.
0‑11	1533	
12‑23	1620	
Total	3153