World Championship of Drivers

Distinction between Formula One and World Championship races
Currently the terms "Formula One race" and "World Championship race" are effectively synonymous; since 1984, every Formula One race has counted towards the World Championship, and every World Championship race has been to Formula One regulations. But the two terms are not interchangeable.
 * the first Formula One race was held in 1947, whereas the World Championship did not start until 1950.
 * in the 1950s and 1960s there were many Formula One races which did not count for the World Championship (e.g., in 1950, a total of twenty-two Formula One races were held, of which only six counted towards the World Championship). The number of non-championship Formula One events decreased throughout the 1970s and 1980s, to the point where the last non-championship Formula One race was held in 1983.
 * the World Championship was not always exclusively composed of Formula One events:
 * The World Championship was originally established as the "World Championship for Drivers", i.e., without the term "Formula One" in the title. It only officially became the Formula One World Championship in 1981.
 * From 1950 to 1960, the Indianapolis 500 counted towards the World Championship. This race was run to AAA/USAC regulations, rather than to Formula One regulations. Only one of the world championship regulars, Alberto Ascari in 1952, started at Indianapolis during this period.
 * From 1952 to 1953, all races counting towards the World Championship (except the Indianapolis 500) were run to Formula Two regulations. Formula One was not "changed to Formula Two" during this period; the Formula One regulations remained the same, and numerous Formula One races were staged during this time.

The distinction is most relevant when considering career summaries and "all time lists". For example, in the List of Formula One drivers, Clemente Biondetti is shown with 1 race against his name. Biondetti actually competed in four Formula One races in 1950, but only one of these counted for the World Championship. Similarly, several Indy 500 winners technically won their first world championship race, though most record books choose to ignore this and instead only record regular participants.