 These include a 2011 perspective piece comparing the effectiveness of supply-side and demand-side laws in reducing rates of abortions performed after 16 weeks which found that the former were much more effective than the latter.He has also published research showing that parental involvement laws were not associated with significant changes in the overall abortion rate, but that they had small effects on some subgroups of minors.In a 2006 study, he and his colleagues found that Texas' parental notification law was associated with a significant decline in the abortion rate among Texas teenagers.