General Electric wanted its employees to stop smoking. They submitted to a Randomized Control Trial where the treatment group received cash incentives to quit. The control group received no incentives. Quitting for 6 months earned you $250, quitting for 12 months $400. The treatment group had 3 times the success rate of the control (14.7% gave up smoking vs 5%), even after financial incentives were discontinued after 12 months (9.4% vs 3.6%). On the strength of this finding, GE now does this for their 152,000 employees.