Misclassification bias and the estimated effect of parental involvement laws on adolescents' reproductive outcomes.

Objectives: We evaluated the presence of misclassification bias in the estimated effect of parental involvement laws on minors' reproductive outcomes when subjection to such laws was measured by age at the time of pregnancy resolution.
Methods: Using data from abortion and birth certificates, we evaluated the effect of Texas's parental notification law on the abortion, birth, and pregnancy rates of adolescents aged 17 years compared with those aged 18 years on the basis of age at the time of pregnancy resolution and age at conception.
Results: On the basis of age at the time of the abortion or birth, the law was associated with a fall of 26%, 7%, and 11% in the abortion, birth, and pregnancy rates, respectively, of 17- relative to 18-year-olds. Based on age at the time of conception, the abortion rate fell 15%, the birth rate rose 2%, and the pregnancy rate remained unchanged.
Conclusions: Previous studies of parental involvement laws should be interpreted with caution because their methodological limitations have resulted in an overestimation of the fall in abortions and underestimation of the rise in births, possibly leading to the erroneous conclusion that pregnancies decline in response to such laws.