UEFA coefficient

In European football, the UEFA coefficients are statistics used for ranking and seeding teams in club and international competitions. Introduced in 1979, the coefficients are calculated by UEFA, who administer football within Europe.

For men's competitions (discussed in this article), three different sets of coefficients are calculated:
 * National team coefficient: used to rank national teams, for seeding in the UEFA Euro qualifying and finals tournaments
 * Country coefficient: used to rank the collective performance of the clubs of each member association, for assigning the number of places, and at what stage clubs enter the UEFA Champions League and the UEFA Europa League
 * Club coefficient: used to rank individual clubs, for seeding in the UEFA Champions League and UEFA Europa League

While not discussed in this article, coefficients are calculated in a similar fashion for women's competitions such as the UEFA Women's Euro and the UEFA Women's Champions League, as well as for youth tournaments such as the UEFA Euro U-21 tournament.

Country coefficient
The country coefficient is used to rank the football associations of Europe, and thus determine the number of clubs from an association that will participate in the UEFA Champions League and the UEFA Europa League.

The UEFA ranking determines the number of teams competing in the season after the next, not in the first season after the publication of the ranking. Thus, the rankings at the end of the 2016–17 season determine the team allocation by association in the 2018–19 (not 2017–18) UEFA season; however, the actual teams that will be participating in the 2018–19 UEFA season are determined at the end of the 2017–18 season when the individual association classifications and national cups are finalized.

Criticisms
The UEFA coefficient system has been criticised for being likely to preserve the status quo for rankings and seedings, as well as for favouring teams from stronger leagues.