WSJ.com: When you design products for the poor, what must you keep in mind?
Mr. Fisher: The No. 1 items will be money-making devices, and money-saving ones only if they’re extremely cheap. You need something easy to maintain without many tools, and something that can be easily transported, because the poor live in remote areas. It can’t require a pickup truck. Human powered — maybe no petrol and no electricity. It has to be energy efficient. You’re dealing with 80 watts of human power.
Mr. Polak: You have a whole different range of affordability when you’re surviving on a dollar a day. We see it a little differently on quality versus affordability. People will pick a product that only lasts two years if it’s cheap. But some of the design principles are the same [as when you design for the rich] — you look at a tool and identify the key contributors to cost and look at ways to design around them.