Defense in baseball is a product of team production in which pitchers and fielders jointly prevent runs. This means that raw run-prevention statistics that economists often use to gauge the value of pitchers, such as earned run average, may not properly assign credit for their performances....

Krautmann contends that Scully’s method for estimating the marginal revenue products of baseball players using team revenues is flawed. Krautmann suggests an alternate method that uses free-agent salaries to impute players' revenue contributions. The Scully method has its weaknesses;...