A Research Note on Trends in the Stock and Flow of Child Support Agreements.

In this research note, we demonstrate that trends in the likelihood of child support agreements differ by marital history (i.e., never-married vs. ever-married) and by whether measures rely on the stock of families (i.e., all those in which children live apart from a parent) or the flow (i.e., those that include children who newly live apart from a parent) in a given year. While previous research has highlighted difference by marital history, the contrast between stock and flow is a new contribution. Trends are typically measured with reference to the stock of cases, even while the flow of cases, which more immediately reflects concurrent policy changes, is more relevant in many contexts. Interpretations of recent declines in child support agreements in the stock of cases-referenced as evidence for both mandating participation and the impracticality of requiring child support-may be better informed by considering the flow of cases. We find the flow of previously married mothers increasingly likely to have child support agreements while the likelihood is relatively consistent over time for never-married mothers. For both groups, using the flow measure, we find notable increases in agreements without payments due in the most recent period. These findings underscore the importance of differentiating stock and flow, and by marital history, in considering the proportion with agreements as an indicator of the effectiveness of current policy.

Noncustodial parents, instrumental networks, and child support compliance.

Research on child support compliance has focused on the characteristics of noncustodial parents (NCPs) that are associated with compliance, finding that compliance with child support orders is primarily related to the ability to pay support as demonstrated by earnings. Yet, there is evidence linking social support networks to both earnings and noncustodial parents' relationships with children. Using a social poverty framework, we show that relatively few NCPs are completely isolated: most have at least some people in their network who can loan money, provide a place to stay, or provide a ride. We explore whether the size of these instrumental support networks is positively linked to child support compliance both directly and indirectly through earnings. We find evidence of a direct association between instrumental support network size and child support compliance, but no evidence of an indirect association via increased earnings. These findings suggest the importance for researchers and child support practitioners to consider the contextual and relational factors of the social networks in which parents are embedded, and to more thoroughly examine the process by which support from one's network can lead to child support compliance.

Synthetic Gene Network with Positive Feedback Loop Amplifies Cellulase Gene Expression in Neurospora crassa.

Second-generation or lignocellulosic biofuels are a tangible source of renewable energy, which is critical to combat climate change by reducing the carbon footprint. Filamentous fungi secrete cellulose-degrading enzymes called cellulases, which are used for production of lignocellulosic biofuels. However, inefficient production of cellulases is a major obstacle for industrial-scale production of second-generation biofuels. We used computational simulations to design and implement synthetic positive feedback loops to increase gene expression of a key transcription factor, CLR-2, that activates a large number of cellulases in a filamentous fungus, Neurospora crassa. Overexpression of CLR-2 reveals previously unappreciated roles of CLR-2 in lignocellulosic gene network, which enabled simultaneous induction of approximately 50% of 78 lignocellulosic degradation-related genes in our engineered Neurospora strains. This engineering results in dramatically increased cellulase activity due to cooperative orchestration of multiple enzymes involved in the cellulose degradation pathway. Our work provides a proof of principle in utilizing mathematical modeling and synthetic biology to improve the efficiency of cellulase synthesis for second-generation biofuel production.

Fathers' Imprisonment and Mothers' Multiple-Partner Fertility.

We consider the intersection between two striking U.S. trends: dramatic increases in the imprisonment of fathers and increases in the proportion of mothers who have children with more than one partner (multiple-partner fertility, or MPF). Using matched longitudinal administrative data that provide unusually comprehensive and accurate information about the occurrence and timing of imprisonment, fertility, and MPF for the population of the state of Wisconsin, we consider the relationship between paternal imprisonment and MPF among unwed mothers. Employing discrete-time event history analysis with multinomial logistic regression, we model the occurrence and timing of the mother's second birth, distinguishing between a birth with the same father and a birth with a different father, and distinguishing between current imprisonment and a history of imprisonment. We find that current imprisonment is associated with an increased likelihood of MPF and a decreased likelihood of fertility with the same father (compared with no additional birth) and that a history of imprisonment is associated with increased MPF in some models but not in our preferred model. To control for unobserved heterogeneity among mothers and assess the evidence of a causal effect of fathers' imprisonment, we also employ the case-time-control method, a fixed-effects method for the analysis of nonrepeated events. Results suggest that fathers' current imprisonment may increase mothers' MPF. Policy implications are discussed.

Who gets custody now? Dramatic changes in children's living arrangements after divorce.

This article reexamines the living arrangements of children following their parents' divorce, using Wisconsin Court Records, updating an analysis that showed relatively small but significant increases in shared custody in the late 1980s and early 1990s. These changes have accelerated markedly in the intervening years: between 1988 and 2008, the proportion of mothers granted sole physical custody fell substantially, the proportion of parents sharing custody increased dramatically, and father-sole custody remained relatively stable. We explore changes in the correlates of alternative custody outcomes, showing that some results from the earlier analysis still hold (for example, cases with higher total family income are more likely to have shared custody), but other differences have lessened (shared-custody cases have become less distinctive as they have become more common). Despite the considerable changes in marriage and divorce patterns over this period, we do not find strong evidence that the changes in custody are related to changes in the characteristics of families experiencing a divorce; rather, changes in custody may be the result of changes in social norms and the process by which custody is determined.

Testing the economic independence hypothesis: the effect of an exogenous increase in child support on subsequent marriage and cohabitation.

We examine the effects of an increase in income on the cohabitation and marriage of single mothers. Using data from an experiment that resulted in randomly assigned differences in child support receipt for welfare-receiving single mothers, we find that exogenous income increases (as a result of receiving all child support that was paid) are associated with significantly lower cohabitation rates between mothers and men who are not the fathers of their child(ren). Overall, these results support the hypothesis that additional income increases disadvantaged women's economic independence by reducing the need to be in the least stable type of partnerships. Our results also show the potential importance of distinguishing between biological and social fathers.

Maternal Re-Partnering and New-Partner Fertility: Associations with Nonresident Father Investments in Children.

Research suggests that paternal re-partnering and new-partner fertility are associated with decreased nonresident father investments in children. Few studies, however, have examined the influence of maternal re-partnering and new-partner births on nonresident father investments. We use data from the National Longitudinal Survey of Youth to examine associations of maternal re-partnering (through cohabitation or marriage with a new partner) and new-partner births with nonresident father visitation and child support payments. Results suggest that maternal re-partnering is associated with a decrease in both yearly father-child contact and child support received by the mother. New-partner fertility for mothers who are co-residing with a partner is associated with an additional decrease in monthly father-child contact, but does not have an additional influence on yearly father-child contact or child support receipt.

The evolution of family complexity from the perspective of nonmarital children.

We document the incidence and evolution of family complexity from the perspective of children. Following a cohort of firstborn children whose mothers were not married at the time of their birth, we consider family structure changes over the first 10 years of the child's life-considering both full and half-siblings who are coresidential or who live in another household. We rely on detailed longitudinal administrative data from Wisconsin that include information on the timing of subsequent births to the mother and father, and detailed information on earnings, child support, and welfare. We find that 60% of firstborn children of unmarried mothers have at least one half-sibling by age 10. Our results highlight the importance of having fertility information for both fathers and mothers: estimates of the proportion of children with half-siblings would be qualitatively lower if we had fertility information on only one parent. Complex family structures are more likely for children of parents who are younger or who have low earnings and for those in larger urban areas. Children who have half-siblings on their mother's side are also more likely to have half-siblings on their father's side, and vice versa, contributing to very complex family structures-and potential child support arrangements-for some children.