In a gleaming office tower in Mexico City secured with retinal scanners, bulletproof glass, and armed guards, dozens of workers in white lab coats dart around a large operations center monitoring long rows of computers. Along one wall, 54 enormous screens flicker dizzyingly with numbers, graphs, and fever charts: a relentless stream of data. You'd think the urgent mission involved tracking the trajectory of a spacecraft or the workings of a national power grid, not tiny amounts of cash and credit for Mexico's working poor.