European Rugby Club Rankings

The European Rugby Club Rankings were introduced for the 2008-09 European season. They were based on the points earned by teams in the now defunct Heineken Cup and the European Challenge Cup over the past four years. They were used to aid in the seeding process for the Heineken Cup and the European Challenge Cup. For the Heineken Cup the first four tiers are defined by these rankings. In addition, the Cup holder is automatically added to the top tier.

Starting with the 2009–10 season, the rankings have the potential to determine one entrant in the following season's Heineken Cup. If England or France produces winners of both European cups in a season, a Heineken Cup berth will be awarded to the highest-ranked team not from that nation and not already qualified to the Heineken Cup. (The winners of both cups receive automatic berths in the next season's Heineken Cup, separately from the allocations of their countries; however, England and France are capped at seven Heineken Cup places apiece.) This scenario will also apply if either of Scotland's two professional teams wins either European cup, since those teams are automatically entered in the Heineken Cup at the start of each season.

Per ERC rule, ties between clubs are broken as follows:

For example, Harlequins and Cardiff Blues are tied on 15 points. Both participated in the 2012–13 Heineken Cup where Harlequins earned 5 points (reached the quarter final) whereas Cardiff only earned 2 points (finished 3rd in their pool). Therefore, Harlequins are ranked higher than Cardiff. Another example: Edinburgh and London Wasps are tied on 11 points. Edinburgh participated in the 2012–13 Heineken Cup (and earned 1 point for finishing 4th in their pool) whereas Wasps played in the 2012–13 European Challenge Cup (and earned 2 points for reaching the quarter finals). Wasps are ranked below Edinburgh even though they earned more points in the 2012–13 season.

...
Wikipedia