Conversely, parents may have low incomes because they are less motivated and skilled and this lesser competence may be exhibited in parenting as well.
Low income may hurt children because low-income families are more likely to have only one parent present, and therefore only half the social and human capital available to the child.
If absence of money itself is the root cause of the negative effects of childhood poverty, then any strategy that increases income will increase child well-being. With more money, parents can provide better nutrition, education, housing, and medical care. They can move to better neighborhoods and enjoy better schools. It may be the case, however, that not all the potential pathways through which child- hood poverty negatively affects child well-being can be “treated” with more money. More money may lower the income stress but not the emotional stress of single parenting, for example. In addition, there may be less human and social cap- ital that results when one parent—only half the potential talent pool for parent- ing—is available.
If marriage increases household income, then marriage would ameliorate the neg- ative effects of childhood poverty that operate through pathways labeled a, b, c, and d above. Marriage may also address at least some of the other pathways through which childhood poverty is associated with relative deprivation (f). But marriage does not address all of the pathways: What if low-income parents are sim- ply less competent generally in parenting as in other domains of life (e)? What if they are less motivated to help their children succeed or have fewer of the skills needed to help their children manage school or work?
To the extent that childhood poverty is caused by living with adults who have per- sistent personality traits or skill deficits that lessen child well-being, neither income supports nor increased marriage alone will “treat” these problems.
Holzer and his colleagues make an adjustment for genetic factors that may be pres- ent in the ability to generate labor market earnings that they believe errs on the side of caution. But not all the selection effects may be understood to be genetic in nature. What if single moms or dads simply are people who have lower average parenting skills and less motivation to begin with? If this is the case, then the use of Holzer’s results for two calculations leads to an overestimate of the taxpayer cost of family fragmentation.
Like Holzer, this analysis is constrained by the availability and quality of relevant empirical evidence. We believe, however, that the way we use Holzer’s results does not lead to an overestimate for at least three reasons:
If the assumptions Holzer and his colleagues used are cautious, then that offsets at least some of the “environmental” effects of having a mother or father with less motivation, whether married or not.