Social welfare refers to the overall welfare of society. With sufficiently strong assumptions, it can be defined as the sum of the welfare of all the individuals in the society. Welfare may be measured either cardinally in terms of "utils" or dollars, or measured ordinarily in terms of Pareto efficiency. The cardinal method in "utils" is rarely used in pure theory today. Its main problem is that different kinds of "utility" cannot easily be summed up without losing the meaning of the measurement. In applied welfare economics money-value estimates are often used. One example of applied welfare economics is cost-benefit analysis. Money-value estimates are a useful form of measurement where income-distribution effects are factored into the analysis or seem unlikely to change the analysis.