Have you ever wondered exactly what a coefficient is?
It's a word referenced regularly throughout the course of each Champions League and Europa League season but not much light is shed on what it actually means.
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It refers, in fact, to UEFA's system of ranking its member clubs and associations for various purposes and can have a big impact on how certain chips fall each year.
To help you get to grips with exactly how it works, Goal has all the information you need to know.
WHAT ARE THE UEFA COEFFICIENTS?
UEFA's coefficient system is a set of numerical ratings given to each of its member associations and the clubs competing in its competitions.
These ratings are then used for various purposes, such as deciding how many qualification spots for the Champions League and Europa League are awarded to each country and how teams are seeded in certain draws.
The ratings are constantly updated, with each result worth a certain number of points that then feeds into a club's overall score.
The scores of each national association's clubs are then used to calculate the rating given to that country's domestic competition as a whole.
HOW ARE THE CLUB RATINGS CALCULATED?
Each club's coefficient is the sum of the points it has gained by recording certain results and achievements over the past five seasons in the Champions League and Europa League.
Those results and achievements are given different point values depending on the competition they occured in and the stage that competition had reached.
For example, a win in the Champions League group stage or later is worth two points, while elimination in the first qualifying round is worth 0.5 points.
A win in the Europa League group stage or later is also worth two points, but to ensure the Champions League teams are appropriately rewarded for facing tougher opponents they are given bigger bonuses for reaching the group stage and the last 16.
The complete list of means by which points can be gained is below.
Champions League points
| Achievement | Points |
|---|---|
| First qualifying round elimination | 0.5 |
| Second qualifying round elimination | 1 |
| Group stage participation | 4 |
| Win (group stage or later) | 2 |
| Draw (group stage or later) | 1 |
| Last-16 participation | 5 |
| Quarter-final participation | 1 |
| Semi-final participation | 1 |
| Final participation | 1 |
Europa League points
| Achievement | Points |
|---|---|
| First qualifying round elimination | 0.25 |
| Second qualifying round elimination | 0.5 |
| Third qualifying round elimination | 1 |
| Play-off elimination | 1.5 |
| Group-stage participation minimum* | 2 |
| Win (group stage or later) | 2 |
| Draw (group stage or later) | 1 |
| Quarter-final participation | 1 |
| Semi-final participation | 1 |
| Final participation | 1 |
*Every Europa League club that reaches the group stage is guaranteed two points, so clubs that fail to win one game or draw two games during that round will receive this as a bonus.
HOW ARE THE ASSOCIATION RATINGS CALCULATED?
The association ratings are derived from the clubs each country has competing in European competition.
The scores of each club from a particular country are added up and then divided by the number of clubs to produce an average, which is the association's rating for that season.
For example, if England had five clubs competing in the Champions League and Europa League and they scored 30, 25, 20, 15 and 10 points, England's rating as an association for that season would be 20.
Like in the club system, the ratings for each of the past five seasons are added up to produce a total score.
The association rankings this produces are used to decide how many European qualification spots each country is allocated.
Currently, the top-four associations in Europe - Spain, England, Italy and Germany - get seven qualification spots: four for the Champions League and three for the Europa League.
WHAT ARE THE CURRENT RANKINGS?
The rankings are constantly updating as matches are played and can be viewed on UEFA's website.
Real Madrid, unsurprisingly, had established supremacy in the club rankings at the end of the 2016-17 season having won their second Champions League in a row.
They were comfortably clear of the group of four teams that followed: Atletico Madrid, Barcelona, Bayern Munich and Juventus.
The struggles of English teams in Europe over recent seasons is highlighted by the fact that Sevilla and Paris Saint-Germain are also closer to first place than the top Premier League club, which was Manchester City.
Who is in last place in the club ranking? That would be FC Prishtina of Kosovo, who played in Europe for the first time in 2017-18.