Consumer surplus : willingness to pay :: marginal analysis : ?

Consumer surplus is the difference between what a buyer is willing to pay for a good and what they actually pay. Similarly, marginal analysis involves comparing the additional benefits of an action against its additional costs. Just as consumer surplus measures the benefit to consumers from purchasing a good at a lower price, marginal analysis helps individuals or businesses decide whether to take an action based on whether the benefits exceed the costs. For example, if a person is willing to pay $50 for a concert ticket but buys it for $30, their consumer surplus is $20. In marginal analysis, if a company considers spending $1,000 on a marketing campaign that is expected to bring in $1,500 in sales, they would assess the $500 gain as a positive outcome, just like the surplus in the first example.