The Bell Curve: Intelligence and Class Structure in American Life

by Richard J. Herrnstein

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 6 16.7457 33.49136 0.000008

  Error 2022 994.6771

  C Total 2028 1011.4228

  RSquare (U) 0.0166

  Observations 2029

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −1.2952650 0.1066175 147.59 0.0000

  zAFQT89 −0.3925580 0.0774209 25.71 0.0000

  zSES +0.1910425 0.0783345 5.95 0.0147

  zAge −0.0278086 0.0617722 0.20 0.6526

  Adult14

  [2 Bio−UnmarMom] −0.1472662 0.117616 1.57 0.2105

  Adult14

  [Bio/Step−UnmarMom] +0.0621918 0.1601525 0.15 0.6978

  Adult14

  [Other−UnmarMom] −0.0872024 0.2553089 0.12 0.7327

  DEPENDENT VARIABLE: First birth out of wedlock.

  SAMPLE RESTRICTIONS: Women with at least one child.

  Basic Analysis:

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 3 39.86862 79.73723 0.000000

  Error 1217 461.90618

  C Total 1220 501.77480

  RSquare (U) 0.0795

  Observations 1221

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −1.9432320 0.0938185 429.01 0.0000

  zAFQT89 −0.6537960 0.1239489 27.82 0.0000

  zSES −0.3052597 0.1189878 6.58 0.0103

  zAge −0.2405246 0.0902516 7.10 0.0077

  The High School Sample:

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 3 15.09449 30.18898 0.000001

  Error 512 187.89956

  C Total 515 202.99405

  RSquare (U) 0.0744

  Observations 516

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −2.1890354 0.1658602 174.19 0.0000

  zAFQT89 −0.7846895 0.2142378 13.42 0.0002

  zSES −0.2428727 0.2165927 1.26 0.2621

  zAge −0.4145066 0.1447961 8.20 0.0042

  The College Sample:

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 3 1.1299340 2.259868 0.520253

  Error 112 4.6193334

  C Total 115 5.7492674

  RSquare(U) 0.1965

  Observations 116

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −6.37685240 3.9705049 2.58 0.1083

  zAFQT89 −0.31644570 1.9844225 0.03 0.8733

  zSES −0.72608390 1.5248314 0.23 0.6340

  zAge +2.58214793 2.8423709 0.83 0.3636

  Basic analysis, Adding Living Arrangements with Adults at Age 14 (Adult 14):

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 6 46.62389 93.24777 0.000000

  Error 1214 455.15091

  C Total 1220 501.77480

  RSquare (U) 0.0929

  Observations 1221

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −1.8260275 0.1541482 140.33 0.0000

  zAFQT89 −0.6620720 0.1259903 27.61 0.0000

  zSES −0.2460336 0.1221771 4.06 0.0440

  zAge −0.2109268 0.0909302 5.38 0.0204

  Adult14

  [2 Bio−UnmarMom] −0.2816545 0.1634249 2.97 0.0848

  Adult14

  [Bio/Step−UnmarMom] +0.2928507 0.206926 2.00 0.1570

  Adult14

  [Other−UnmarMom] −0.4991684 0.3593261 1.93 0.1648

  Basic analysis, Adding Presence of Biological Parents at Age 14 (14Bio):

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 6 47.56391 95.12783 0.000000

  Error 1214 454.21088

  C Total 1220 501.77480

  RSquare (U) 0.0948

  Observations 1221

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −2.0199123 0.2037839 98.25 0.0000

  zAFQT89 −0.6567746 0.1250691 27.58 0.0000

  zSES −0.2479794 0.1214895 4.17 0.0412

  zAge −0.2037178 0.0910296 5.01 0.0252

  14Bio

  [MomOnly−PopOnly] +0.6528652 0.2233927 8.54 0.0035

  14Bio

  [Mom/Pop−PopOnly] −0.0862208 0.2102335 0.17 0.6817

  14Bio[Neither−PopOnly] −0.2371231 0.4150982 0.33 0.5678

  Basic Analysis, Adding Poverty Status in the Calendar Year Prior to Birth (PreBirthPov):

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 4 63.21118 126.4224 0.000000

  Error 956 292.73717

  C Total 960 355.94835

  RSquare (U) 0.1776

  Observations 961

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −1.6785743 0.1460018 132.18 0.0000

  zAFQT89 −0.6300049 0.1665952 14.30 0.0002

  zSES −0.1828877 0.1513393 1.46 0.2269

  zAge −0.4759393 0.127232 13.99 0.0002

  PreBirthPov A

  [No−Yes] −0.8178684 0.1266496 41.70 0.0000

  Basic Analysis, Restricted to Women Below the Poverty Line in the Calendar Year Prior to Birth:

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 3 3.005867 6.011735 0.111041

  Error 95 65.003329

  C Total 98 68.009196

  RSquare (U) 0.0442

  Observations 99

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −0.65306390 0.2901964 5.06 0.0244

  zAFQT89 −0.76887410 0.3453889 4.96 0.0260

  zSES +0.17993445 0.2589166 0.48 0.4871

  zAge −0.13622880 0.2289764 0.35 0.5519

  CHAPTER 9: WELFARE DEPENDENCY

  DEPENDENT VARIABLE: On welfare by the first calendar year after the birth of the child.

  SAMPLE RESTRICTIONS: Women with at least one child born prior to January 1, 1989.

  Basic Analysis, Adding Poverty Status in the Year Prior to Birth (PreBirthPov) and Marital Status at the Time of the Birth (BStatus):

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 5 100.37993 200.7599 0.000000

  Error 833 221.75844

  C Total 838 322.13837

  RSquare (U) 0.3116

  Observations 839

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −1.03594055 0.1713324 36.56 0.0000

  zAFQT89 −0.57972844 0.1892548 9.38 0.0022

  zSES −0.06130137 0.1746782 0.12 0.7256

  zAge −0.11269946 0.1457313 0.60 0.4393

  PreBirthPov

  [No−Yes] −0.89960808 0.1446041 38.70 0.0000

  BStatus

  [Illegit−Legit] +1.05258560 0.1352006 60.61 0.0000

  The High School Sample, Adding Poverty Status in the Year Prior to Birth (PreBirthPov) and Marital Status at the Time of theBirth (BStatus):

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 5 29.28354 58.56707 0.000000

  Error 384 108.14153

  C Total 389 137.42507

  RSquare (U) 0.2131

  Observations 390

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −1.44834110 0.2659616 29.41 0.0000

  zAFQT89 −0.60735910 0.3004261 4.09 0.0432

  zSES +0.12094082 0.3096641 0.15 0.6961

  zAge −0.24139690 0.2089849 1.33 0.24
81

  PreBirthPov

  [No−Yes] −0.67898980 0.223275 9.25 0.0024

  BStatus

  [Illegit−Legit] +0.80812194 0.2058033 15.42 0.0001

  The College Sample: Omitted. Included no women who had received Aid to Families with Dependent Children (AFDC) within a year after the birth.

  DEPENDENT VARIABLE: On welfare for at least five years versus women with no welfare experience at all.

  SAMPLE RESTRICTIONS: Women with at least one child born prior to January 1, 1986. For women scored as “no welfare,” child born after December 31, 1977 and complete data on welfare receipt from 1978 to 1986.

  Basic Analysis, Adding Poverty Status in the Year Prior to Birth (PreBirthPov) and Marital Status at the Time of the Birth(BStatus):

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 5 44.82635 89.65269 0.000000

  Error 493 96.90156

  C Total 498 141.72790

  RSquare (U) 0.3163

  Observations 499

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −1.5840878 0.2826002 31.42 0.0000

  zAFQT89 −0.5506878 0.2950687 3.48 0.0620

  zSES −0.4921959 0.2779368 3.14 0.0766

  zAge −0.1094338 0.2276355 0.23 0.6307

  PreBirthPov

  [No−Yes] −0.7636358 0.2336359 10.68 0.0011

  BStatus

  [Illegit−Legit] +1.1951879 0.205013 33.99 0.0000

  The High School Sample, Adding Poverty Status in the Year Prior to Birth (PreBirthPov) and Marital Status at the Time of theBirth (BStatus):

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 5 13.898589 27.79718 0.000040

  Error 251 48.695997

  C Total 256 62.594585

  RSquare (U) 0.2220

  Observations 257

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −1.7786656 0.3901684 20.78 0.0000

  zAFQT89 −0.2301309 0.4429317 0.27 0.6034

  zSES −0.3131157 0.4832739 0.42 0.5170

  zAge −0.0377430 0.3173131 0.01 0.9053

  PreBirthPov

  [No-Yes] −0.6891978 0.3355851 4.22 0.0400

  BStatus

  [Illegit-Legit] +1.1068557 0.307595 12.95 0.0003

  The College Sample: Omitted. The cross-sectional College Sample included no women who were on chronic welfare within a year after the birth.

  CHAPTER 10: PARENTING

  DEPENDENT VARIABLE: Did the mother smoke during pregnancy?

  SAMPLE RESTRICTIONS: None.

  Basic Analysis:

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 3 84.6762 169.3523 0.000000

  Error 2338 1443.8251

  C Total 2341 1528.5013

  RSquare (U) 0.0554

  Observations 2342

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −0.65729780 0.0465003 199.81 0.0000

  zAFQT89 −0.63479220 0.0645408 96.74 0.0000

  zSES −0.13376440 0.0604787 4.89 0.0270

  zAge +0.09727632 0.0484283 4.03 0.0446

  DEPENDENT VARIABLE: Low birth weight (weight less than 5.5 pounds at birth).

  SAMPLE RESTRICTIONS: Excludes premature babies whose weight was less than 5.5 lbs. but was appropriate for gestational age.

  Basic Analysis:

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 3 6.55199 13.10397 0.004417

  Error 2273 349.79375

  C Total 2276 356.34574

  RSquare (U) 0.0184

  Observations 2277

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −3.40600010 0.1270004 719.25 0.0000

  zAFQT89 −0.44308170 0.1496847 8.76 0.0031

  zSES +0.03312669 0.1492929 0.05 0.8244

  zAge +0.26896236 0.1226929 4.81 0.0284

  Basic Analysis, Adding Poverty Status in the Year Prior to Birth (PreBirth-Pov):

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 4 9.09299 18.18599 0.001135

  Error 1859 298.98002

  C Total 1863 308.07301

  RSquare (U) 0.0295

  Observations 1864

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −3.12509860 0.16455 360.69 0.0000

  zAFQT89 −0.45583800 0.1674174 7.41 0.0065

  zSES +0.02995737 0.1628609 0.03 0.8541

  zAge +0.34292817 0.1342861 6.52 0.0107

  PreBirthPov

  [No-Yes] −0.28644950 0.15725 3.32 0.0685

  Basic Analysis, Adding Mother’s Age at Birth (AgeBirth):

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 4 6.77955 13.55909 0.008844

  Error 2272 349.56619

  C Total 2276 356.34574

  RSquare (U) 0.0190

  Observations 2277

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −3.90965790 0.7617514 26.34 0.0000

  zAFQT89 −0.46251520 0.1522804 9.22 0.0024

  zSES +0.01584480 0.1517047 0.01 0.9168

  zAge +0.25360789 0.1252257 4.10 0.0428

  AgeBirth +0.02095854 0.0311104 0.45 0.5005

  The High School Sample:

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 3 1.96999 3.93998 0.268019

  Error 944 179.09080

  C Total 947 181.06079

  RSquare (U) 0.0109

  Observations 948

  Parameter Estimates:

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −3.1278597 0.1778908 309.16 0.0000

  zAFQT89 −0.3560319 0.2387034 2.22 0.1358

  zSES +0.0653651 0.2379847 0.08 0.7836

  zAge +0.2490558 0.1681270 2.19 0.1385

  The College Sample: Omitted. The cross-sectional College Sample included only four low-birth-weight babies.

  DEPENDENT VARIABLE: The child’s mother was under the poverty line throughout the child’s first three years of life.

  SAMPLE RESTRICTIONS: Includes children born from January 1, 1978 through December 31, 1987, with complete data on poverty for the first three years of the child’s life, beginning with the calendar year of birth. Comparison group consists of children of mothers who were not in poverty in any of those years.

  Basic Analysis:

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 3 79.84242 159.6848 0.000000

  Error 1054 246.63029

  C Total 1057 326.47271

  RSquare (U) 0.2446

  Observations 1058

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −2.9319316 0.1679177 304.87 0.0000

  zAFQT89 −1.1608860 0.1893877 37.57 0.0000

  zSES −1.0386253 0.1734586 35.85 0.0000

  zAge −0.1837537 0.1320334 1.94 0.1640

  Basic Analysis, Adding Poverty Status in the Year Prior to Birth (PreBirthPov):

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 4 13338437 266.7687 0.000000

  Error 967 161.88379

  C Total 971 295.26816

  RSquare(U) 0.4517

  Observations 972

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −1.9685017 0.2117444 86.43 0.0000

  zAFQT89 −1.0772447 0.2375948 20.56 0.0000

  zSES −0.8977385 0.2215879
16.41 0.0001

  zAge +0.0117316 0.1681889 0.00 0.9444

  PreBirthPov

  [No-Yes] −1.7345986 0.1635206 112.53 0.0000

  The High School Sample, Adding Poverty Status in the Year Prior to Birth (PreBirthPov):

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 4 68.47634 136.9527 0.000000

  Error 472 75.99609

  C Total 476 144.47243

  RSquare (U) 0.4740

  Observations (or Sum Wgts) 477

  Parameter Estimates

  Term Estimate Std Error ChiSquare Prob>ChiSq

  Intercept −1.9504069 0.3232654 36.40 0.0000

  zAFQT89 −1.2253622 0.4168866 8.64 0.0033

  zSES −0.5574476 0.3852681 2.09 0.1479

  zAge 0.05808314 0.252284 0.05 0.8179

  PreBirthPov

  [No-Yes] −2.0368386 0.236268 74.32 0.0000

  The College Sample: Omitted. The cross-sectional College Sample included only one child whose mother was beneath the poverty line throughout the first three years.

  DEPENDENT VARIABLE: The child’s HOME index score was in the bottom decile.

  SAMPLE RESTRICTIONS: None.

  ADDITIONAL CONTROL VARIABLES: Test year (TestYr, nominal: 1986, 1988, or 1990) and the child’s age category for scoring the HOME index (HomeAgeCat, nominal, in years: 0/2, 3/5, 6+).

  Basic Analysis:

  Whole-Model Test

  Source DF -LogLikelihood ChiSquare Prob>ChiSq

  Model 7 88.9225 177.8451 0.000000

  Error 5114 1190.6267

  C Total 5121 1279.5492

  RSquare (U) 0.0695

  Observations 5122

  Patameter Estimates

  Term Estimate Std Error ChiSquare Prob>