Knowledge of treatment effect heterogeneity or "essential heterogeneity" plays an important role in our understanding of how programs work and in the design of systems to allocate them among the eligible. This paper provides a relatively non-technical survey of the current state of the treatment...

"Medical practitioners typically utilize the following protocol when advising pregnant women about testing for the possibility of genetic disorders: Pregnant women over the age of 35 should be tested for Down syndrome and other genetic disorders; for younger women, such tests are discouraged...

We examine Becker's (1960) contention that children are "normal." For the cross section of non-Hispanic white married couples in the U.S., we show that when we restrict comparisons to similarly-educated women living in similarly-expensive locations, completed fertility is positively correlated...