Bounding Causal Effects Using Data from a Contaminated Natural Experiment: Analysing the Effects of Teenage Childbearing

In this paper, we consider what can be learned about causal effects when one uses a contaminated instrumental variable. In particular, we consider what inferences can be made about the causal effect of teenage childbearing on a teen mother's subsequent outcomes when we use the natural experiment of miscarriages to form an instrumental variable for teen births. Miscarriages might not meet all of the conditions required for an instrumental variable to identify such causal effects for all of the observations in our sample. However, it is an appropriate instrumental variable for some women, namely those pregnant women who experience a random miscarriage. Although information from typical data sources does not allow one to identify these women, we show that one can adapt results from Horowitz and Manski (1995) on identification with data from contaminated samples to construct informative bounds on the causal effect of teenage childbearing. We use these bounds to re-examine the effects of early chilbearing on the teen mother's subsequent educational and labour market attainment as considered in Hotz, McElroy and Sanders (1995a, 1995b). Consistent with their study, these bounds indicate that women who have births as teens have higher labour market earnings and hours worked compared to what they would have attained if their childbearing had been delayed.

[1]  James J. Heckman,et al.  Randomization as an Instrumental Variable , 1995 .

[2]  Michael D. Perlman,et al.  One-Sided Testing Problems in Multivariate Analysis , 1969 .

[3]  V. J. Hotz,et al.  The costs and consequences of teenage childbearing for mothers. , 1995 .

[4]  J. Heckman,et al.  Instrumental Variables: A Cautionary Tale , 1995 .

[5]  J. Angrist,et al.  Identification and Estimation of Local Average Treatment Effects , 1995 .

[6]  F. Wolak.  Testing inequality constraints in linear econometric models , 1989 .

[7]  Joel L. Horowitz,et al.  Identification and Robustness with Contaminated and Corrupted Data , 1995 .

[8]  M R Rosenzweig,et al.  Sisters, siblings, and mothers: the effect of teen-age childbearing on birth outcomes in a dynamic family context. , 1995, Econometrica : journal of the Econometric Society.

[9]  Charles F. Manski,et al.  What Can Be Learned about Population Parameters when the Data Are Contaminated?: Robust Inference , 1995 .

[10]  T. Trussell.  Economic consequences of teenage childbearing. , 1976, Family planning perspectives.

[11]  C. Manski.  What Do Controlled Experiments Reveal About Outcomes When Treatments Vary , 1993 .

[12]  James J. Heckman,et al.  Assessing the Case for Social Experiments , 1995 .

[13]  W. Härdle.  Applied Nonparametric Regression , 1991 .

[14]  D. Upchurch,et al.  The Timing of a First Birth and High School Completion , 1990 .

[15]  L. Waite,et al.  The Impact of an Early First Birth on Young Women's Educational Attainment , 1978 .

[16]  C. Manski.  Nonparametric Bounds on Treatment Effects , 1989 .

[17]  J. Kline,et al.  Conception to Birth: Epidemiology of Prenatal Development , 1989 .

[18]  M. Marini.  Women's Educational Attainment and the Timing of Entry into Parenthood. , 1984 .

[19]  C. Manski.  Anatomy of the Selection Problem , 1989 .

[20]  Howard S. Bloom,et al.  Accounting for No-Shows in Experimental Evaluation Designs , 1984 .

[21]  Jeffrey A. Smith,et al.  Making the Most Out of Social Experiments: Reducing the Intrinsic Uncertainty in Evidence from Randomized Trials with an Application to the Jtpa Exp , 1994 .

[22]  Charles F. Manski,et al.  Alternative Estimates of the Effect of Family Structure during Adolescence on High School Graduation , 1992 .

[23]  J. Heckman,et al.  Longitudinal Analysis of Labor Market Data: Alternative methods for evaluating the impact of interventions , 1985 .

[24]  L. Wise,et al.  Teenage mothers and teenage fathers: the impact of early childbearing on the parents' personal and professional lives. , 1978, Family planning perspectives.

[25]  Jeffrey Grogger,et al.  The Economic Consequences of Unwed Motherhood: Using Twin Births as a Natural Experiment , 1994 .

[26]  S. Korenman,et al.  The Socioeconomic Consequences of Teen Childbearing Reconsidered , 1991 .

[27]  James J. Heckman,et al.  Characterizing Selection Bias Using Experimental Data , 1998 .