A 1-percent increase or decrease in milk prices increases or decreases U.S. milk production a total of about half of 1 percent over a 4-year period. This study measures the effects of changes in major economic factors of milk production on the amount of milk dairy farmers produce. The major factors include prices farmers receive for milk; input costs of running a dairy farm (measured here by prices of alfalfa hay and corn); profits farmers would receive in alternative farm enterprises (measured by beef prices and, again, feed prices); and general economic conditions (measured by the unemployment rate).