Last week I wrote about “treatment as prevention.” Because being treated by a combination of ARV drugs effectively prevents the transmission of HIV from an infected person to his (her) uninfected partner, the idea is that if we were to test as many people as possible, find out who is infected, and offer them ARVs, we could make significant headway in preventing the spread of HIV. In other words, test and treat.
Regardless of whether we do empirical or theoretical work, we all have to utilize information given to us by others. In the field of development economics, we rely heavily on surveys of individuals, households, facilities, or firms to find out about all sorts of things. However, this reliance has been diminishing over time: we now also collect biological data, try to incorporate more direct observation of human behavior, or conduct audits of firms.