The basic idea that incentives can be used to motivate behavior is a powerful one. It works for employees, and it has a clear place in parenting, as anyone who has tried to potty-train a recalcitrant toddler with sticker rewards knows.

Even if you are planning a birth with an epidural, the evidence suggests that a doula can help make things go much more smoothly.

Even though it is the case that poverty is linked to AIDS, in the sense that Africa is poor and they have a lot of AIDS, it's not necessarily the case that improving poverty - at least in the short run, that improving exports and improving development - it's not necessarily the case that that's going to lead to a decline in HIV prevalence.

Talking to women about birth can be polarizing.

I tell my micro students everything I teach them is important, but the truth is that some things are more useful than others, and opportunity cost is near the top.