Richard J. Murnane, Sean F. Reardon, Preeya P. Mbekeani and Anne Lamb:

To explore these questions, we examine enrollment and family-income data from the past 50 years at Catholic, other religious, and nonsectarian private elementary schools (that is, schools serving grades K–8). Our analysis finds that private schools, like public schools, are increasingly segregated by income. In particular, the share of middle-income students attending private schools has declined by almost half, while the private-school enrollment rate of wealthy children has remained steady. Much of the decline among middle-income students is due to falling enrollment at Catholic schools, which have closed in droves in the past 20 years. Meanwhile, private-school enrollment among affluent students has shifted from religious to nonsectarian schools.