At the start of the study, the average number of bars of soap households used was not zero. It was two bars per week. In other words, they already had soap. So what did the study really change? Well, two things, Luby told me. First, “We removed the economic restraint on purchasing soap. People say soap is cheap and most households have soap. But we wanted people to wash a lot. And people are quite poor. So we removed that as a barrier.” Second, and just as important, the project managed to make soap use more systematic.
