This tool calculates a ratio of cost to a non-monetary benefit or outcome. The focus may be on one domain of impact (e.g. crime, student achievement) or multiple areas of impact. However, measures of cost-effectiveness can only account for one area of program impact at a time. Since program impacts are measured in natural units (e.g. life year saved, child graduating from high school), unless those units are common across all areas of impact, it is not possible to aggregate across them.