EPGP is based on the concept of Effort Points and Gear Points. Effort Points quantify the effort each member put towards the (common) guild goals and Gear Points quantify what each member got back in return. Loot priority is computed as the quotient of the two; priority (PR) is equal to EP/GP.
In a sense EPGP is like zero sum, but without all the need to rebalance the system, or impose taxes to give points for other effort put into the guild. Zero sum awards GP/N points to each player for each item dropped (GP the value of the item and N the number of players in the raid) so that the sum of all points for the members of the guild is zero. EPGP on the other hand is by definition self balanced since priority (and hence chance to receive loot) is directly proportional to the effort you put and inversely proportional to the rewards you got. It is also much more flexible than zero sum since it doesn't require a specific balance point (sum to be equal to zero for example). As such points can be awarded for almost anything without any taxation or over complicating the system (see below). Also another problem with zero sum is the random value of each boss. A boss kill is a boss kill and the effort to kill it is the same no matter if it happened to drop 1 or 2 epics. With zero sum since the amount of effort points the members get is proportional to the loot dropped which is definitely not representing fairly the effort each member puts in the guild.
EP can be awarded through a multiple activities:
* Being on time for raids
* Killing bosses
* Wiping on new boss tries
* Being present until the end of raid
* Being extraordinarily helpful to the guild (making pots for a specific fight)
* Doing some grunt work no one wants to tackle, like updating the guild's website
GP points are accounted through some other set of action:
* Receiving loot in a raid
* Receiving items from the guild bank for high level enchants
* Getting gold from bank for repairs/mats
Clearly each guild can choose to use any combination (or even come out with its own point assignment) of the above points. Assignment of points for each activity/action is not something that EPGP tries to solve. This is solely left to the guild management, as it is out of the scope of the core of the system (and is also the case with many popular loot systems).
Another twist in EPGP, that makes it different than other loot systems is the fact that EP and GP decay over time. The decay can be set by the guild master (it can also be disabled if it is set to zero). With a decay of N%, after each raid the guild participates in, each member gets her EP and GP reduced by N%. This eliminates EP (DKP) hoarding.
Because of the fact that EP decays over time, we can use a simple metric to estimate attendance: Min EPs. Given a value for Min EPs we choose to give PR = 0 to those that have less than Min EPs. As an example, assume a guild where about 500 EPs are awarded per member per raid and a Decay of 10%. If Min EPs is set to 1300 then a member needs to be in at least the last 3 raids to be eligible for loot (500+450+405), or the last 4 raids before the last one 450+405+365+329. This is arguably a better measure than attendance, as attendance is a somewhat loose criterion: if a member came to a raid for 1 hour only and the rest were in it for 4, do they all count as the attended the raid? Since EP measures the effort of each member, having a Min EP puts the cut-off at an effort point which will work both for new members and old members. An old member that is idle for a long time will loose EPs gradually so she might get lower than Min EPs which makes her ineligible for loot. A new member starts with EP equal to zero so he needs to attend some raids in order to get his EP above Min EP to be eligible for loot.
Another way to combat people with 0 GP skyrocketing on the PR meters (trials or inactive members that just became active) is with Base GP. With Base GP set to X everyone's effective GP becomes X + Individual GP. Effective GP will never go below X. Using Base GP has a major ramification:
* GP decays faster than EP. This is because on every decay you decay an extra Base GP D
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