 Complex problems can have simple solutions. For example, many blood tests require separating blood. Separating blood requires a centrifuge, and a centrifuge requires electricity. The problem is, is in that many parts of the world, there is no electricity, so blood must be refrigerated and transported to a facility that has one. This egg beater you see here solves this problem. It was designed by white signing colleagues to be a hand-powered centrifuge, what you do is you put blood in the bottom of the tube and crank the egg beater to separate the blood. Whiteside's egg beater can work in a remote village without electricity. In the 1960s, China was faced with the problem of how to provide health care to the remote countryside. Their solution was to train farmers to be barefoot doctors. These barefoot doctors were able to provide simple yet effective treatments. Whiteside's egg beater is the kind of technology that I can imagine a barefoot doctor would want to carry in their toolkit. The question I want to raise here is, can we carry the idea of providing simple yet effective tools from the technological world to the psychological world? For example, when a child has a cough and fever, they may have pneumonia. The problem is that the doctor has to prescribe antibiotics before there's time to get conclusive tests back from the lab. Fisher and colleagues design this very simple decision rule to help the doctor decide what to do. It asks just two questions. The first question is, have the child had a fever for more than two days? If the answer is no, no antibiotics are given. If the answer is yes, we move to the second question. Is the child older than three? Again, if the answer is no, no antibiotics are given. If the answer is yes, then they're prescribed. And this tree reduces the number of unnecessary antibiotic prescriptions. It is simple decision rules like this that we study in our group. We call them fast and frugal. They're frugal in that they tend to use very few pieces of information. They're fast in that they do not combine this information in complicated ways. This work is inspired by the ideas of bounded rationality that Herbert Simon championed. Simon argued that human decision making is bound by what people can and can't do. So we followed his imperative to study how people go about making decisions and we've come to learn that people can make effective decisions even when they have very little information and time to go on. We have spent years and years in computer simulation, mathematical analysis, and behavioral experiments trying to understand how these simple rules perform as well as they do. And now we believe we're at a point where we can devise simple yet effective strategies that we'd like to share. Let me turn to some examples from finance. So can we predict whether a bank is going to fail? Some of my colleagues along with their colleagues at the Bank of England are trying to answer just this question. They've devised a simple rule which asks just a few questions such as does the bank have too many loans relative to its assets. They compared this simple rule to a standard statistical technique and they found that in comparison the simple rule is better able to flag banks which are likely to fail. But to be fair, the standard rule is better able to give a healthy bank a clean bill of health. Big banks can be brought down by bad loans. Muhammad Yunus has championed the idea that very small loans, micro-sized loans, can help lift poor people out of poverty. The key to this idea is the idea of a lending group or a joint liability group. And what this is essentially is a group of people get together and they have to decide they're going to take out a loan and then they're liable for each other's loan. So if one of them doesn't pay, then another has to. So a question we might ask, can we devise simple rules which will help people figure out who is the best person to put in their joint liability group? And this is the kind of information that a loan officer in the field may want to have. I've told you about some simple pieces of technology. I told you about Whiteside's egg beater. I told you about the antibiotic rule. I told you about the bad bank rule. And the question I want your help with, the question I want to discuss here, is can we bring simple rules to the world of micro-finance? Thank you.