DEFINITION of 'Doctor Copper' Market lingo for the base metal that is reputed to have a Ph.D. in economics because of its ability to predict turning points in the global economy. Because of copper's widespread applications in most sectors of the economy - from homes and factories, to electronics and power generation and transmission - demand for copper is often viewed as a reliable leading indicator of economic health. This demand is reflected in the market price of copper. Generally, rising copper prices suggest strong copper demand and hence a growing global economy, while declining copper prices may indicate sluggish demand and an imminent economic slowdown.