Please visit GiveWell.org This CharityScorecard.org site was in use from 2006 to 2008, but is now mostly dormant, and the material here is out of date. The GiveWell project has similar goals and is being actively maintained. I've left the old CharityScorecard.org content here just for the historical record.

From CharityScorecard

Disability-Adjusted Life Year (DALY) 

A DALY is a unit of measurement that's widely-used when trying to measure health outcomes. DALYs are measured by taking into account the years of life gained and the years that are lived with some disability, with a weighting for the severity of the disability. For example, if a 35-year-old smoker quits smoking, they might gain 8 DALYs. A new national tax on cigarettes in some country might save 12,000,000 DALYs. See also: Year of Life Lost (YLL), the World Health Organization DALY definition, and the Wikipedia DALY entry.