There are several formulas available for arranging a round robin tournament. It is common for organizers to give numerical assignments to each participant, arrange the contests, and then shift all but one fixed participant in subsequent rounds by one spot (with the last participant moving to the top non-fixed spot). Other mathematically sound methods do exist to form round robin tournaments. Websites such as tournamentscheduler.net randomly organize contests to fit round robin requirements.
To set up a round robin tournament, you need to organize contests so that every participant (or team) faces off against every other team once. This differs from elimination tournaments, where a team is ejected after an initial loss. This setup is often used for sporting competitions with a large number of competitors; the 2018 FIFA World Cup tournament will use a round robin arrangement to select qualifiers to advance in the second and third rounds of the tournament.
A double round robin is similar to the standard round robin; however, a double round robin tournament has each competitor play every other competitor in the contest twice. The American Football League of 1940-1941 was the first American football league to use the double round robin format to structure its season.