Weighted Sum Model

The weighted sum model (WSM), also known as weighted linear combination or simple additive weighting, is the best known and simplest method of multi-criteria decision analysis for evaluating alternatives against several criteria. Each criterion is assigned a relative weight of importance, each alternative is scored on every criterion, and a total score for each alternative is calculated by multiplying each criterion's performance value by its weight and summing the products, with the highest total score identifying the best alternative in a maximization problem. The method requires every criterion to be expressed in the same units, since combining measurements from different scales, the source notes, is like adding apples and oranges.