I've been working on this for quite a while, which I've mentioned in a number of different places. I posted an earlier draft of this concept in the AI3 vs AI4 thread, but since then it's gotten a few different refinements, and I've decided it's time for some peer review.
For quite some time, we've had the False God Efficiency Index (FGEI) in order to accurately determine the average profit for various FG farming decks. However, every other target has been limited to studies of win rate and TTW which are only tracked within that given target. There has been no easy way to determine whether it's better to go for a fast deck with a mediocre win rate, or a high win rate deck with mediocre speed, and where the balance is between speed, win rate, and EM rate. On top of that, there are wildly conflicting opinions on which AIs provide the most actual profit over time.
There is no reason that the principles used in FGEI can't be applied to the other AI targets in order to arrive at an actual number, similar to FGEI, representing net profit over time. Such formulae would make it quite simple to accurately rank decks in the various studies by net profit rather than by either win rate or TTW alone, as has been traditionally done. Additionally, once every deck has an expected profit over time easily attached to it, it becomes trivial to determine the actual advisability of farming the various AI targets. As a side effect, it would answer questions about the breakpoint where it's more profitable to farm gold or platinum (for example) depending on which way the rewards of each have moved.
Put as simply as possible, the net profit of a deck is as follows:
(((Non-EM wins over a time period) * (Average profit per Non-EM win)) + ((EM wins over a time period) * (Average profit per EM win))) * (Average percentage of extra HP)) - ((Losses over a time period) * (Cost per loss)) + ((Wins over a time period) * (Average spins profit per win)) + ((Special spins over a time period) * (Average special spin profit))
TimeFirst of all, the words "over a time period" are everywhere through the formula, so we'll start there. In the interest of removing as much subjectivity from the formula as possible, the formula will use a number of turns as a unit of time rather than an hour or any actual unit of time. While it is certainly possible to convert this formula to use actual units of time rather than a number of turns, the speed people play is highly variable and is also dependent on computer/ISP/network conditions.
I have not completely finished studying the relationship between turns and actual units of time yet, but looking at the limited information available in various studies which have tracked seconds per game, there appears to be relatively little overall variation within a given target even with different types of decks, but there is great variation between different players with similar decks against identical targets. This leads me to believe we're never going to arrive at a perfect answer here, but as things like the 1.32 FGEI study get further along, I'll have more source data to work from. Ideally we could start getting game time recorded in the various studies (as is already done in FGEI) just so we can have information rather than just opinions.
Personally, I assume that there are 333 turns per hour, which works out to around 10.8 seconds per turn. Looking at (quite outdated) AI3 studies puts AI3 at a bit faster than this on average (though, like I said, there's a good bit of variance based on player). If you assume that decks take the same amount of time per turn (which they don't, but it's actually pretty close), turns per hour is actually pretty much irrelevant unless you want to compare the result of this formula to FGEI. If you're a slower player, 250 per hour may be a better choice for you; in that case, multiply the resulting OUEI of 333 TPH by 0.75.
As far as the difference in time per turn between decks goes, as I said, I hope to have better information later, but for now, this part has to remain one of the two places in this formula which are just plain subjective. If you feel that you play a given deck slower per turn than what you're comparing it to (or than average, or whatever), multiply the number this formula produces by 0.9 or whatever you would like. This formula will (until there's a better way to do this) assume the same number of turns per hour for all decks.
Time TL;DR: Turns per hour ("TPH") = 333. All decks are the same (until we have better information)
Wins/LossesI hope this is the least controversial part of this entire article. Win rate ("WR") is (Wins / (Wins + Losses)). Loss rate ("LR") is (1 - Win Rate).
Wins/Losses TL;DR: It's like 15 words long.
Turns per WinThe next step is to convert turns to win and win rate into an average turns per win. First of all, this formula assumes that turns to lose is equal to turns to win. It isn't always, but IMO it's the best way to handle the subject, and that also seems to be the general opinion of the community when it's been discussed elsewhere. This is certainly open to debate, but as TTL isn't routinely tracked in various studies, if you decide TTL != TTW, this whole formula is useless until we redo basically all the studies.
So anyway, from now on, TTL = TTW. In order to get turns per win, all you have to do is take TTW and divide by win rate. For example, a deck with 10 TTW and a 50% win rate averages 20 turns per win (10 / 0.5), and a deck with 10 TTW and 75% win rate averages 13.33 turns per win. Honestly, if you're only comparing decks within a given target, you can just about stop here, as turns per win is generally speaking the biggest determining factor of a deck's overall profit as compared to other decks against the same target.
Turns per win TL;DR: Turns per win ("TPW") is turns to win ("TTW") divided by win rate. Turns to lose are not considered and assumed to be equal to TTW.
EMsEM rate is EMs divided by wins. It is
not EMs divided by total games.
Rather than handling EMs separately, it's easier to combine the profit from EMs into the profit from regular wins. It's completely identical mathematically, but it makes for a simpler formula. This is done by multiplying the total win value over time by (1 + (EM rate) * (Factor representing difference between EM value and non-EM value)). That will allow you to arrive at a total value for all the wins (while considering EMs) as one item in the formula rather than breaking non-EM profit and EM profit into two different steps.
EM TL;DR: EM Rate ("EMR") = (EMs / Wins).
Win/loss valueEvery AI target has a stated value - the number shown as "reward" for AI# targets, and the number of electrum shown by the league for arena. Arena and AI3 have a win value of between 0.5 the stated value and one less than the stated value. AI4 has a win value of between 0.375 the stated value and one less than the stated value. AI3 and AI4 have a loss value of 0.5 the stated value. All arena have a loss value of 15 (assuming you rate the deck which beat you). FGEI assumes that an average FG win is worth 47 electrum, which works out to a 50 hp victory. This formula assumes the same, or 75.00% of the stated value for arena and AI3. A 50 hp victory against AI4 works out to 68.75% of the stated value (as it increases linearly).
An EM victory is worth double the stated value. As noted above, EM profit can be factored in with non-EM profit by multiplying base win profit (for all wins) by (1 + (EM Rate) * (Factor representing difference between EM value and non-EM value)). 200% divided by 75.00% gives an EM factor of 1.67 for AI3 and arena, and 200% divided by 68.75% gives an EM factor of 1.91 for AI4. Note that the EM factors are one less than the result of the division in order to avoid double-counting the original win. Therefore, total win value for AI3/arena is ((Stated value * 0.75) * (1 + (EM Rate * 1.67))), and for AI4 is ((Stated value * 0.6875) * (1 + (EM Rate * 1.91))).
Win/loss value TL;DR: Win value ("WV") = ((Stated Value ("SV") * 0.75) * (1 + EMR * 1.67)) for AI3/arena, and ((Stated Value ("SV") * 0.6875) * (1 + EMR * 1.91)) for AI4. Loss Value ("LV") = 15 for arena, and (0.5 * SV) for AI#.
Extra HPThis is the other subjective part of the formula. You need to apply a multiplier to the win value based on whether/how much max HP boost the deck gets. There are no studies about the average number of SoDs that, say, pdials gets off before it wins. I personally have decided, completely arbitrarily, that assuming about 2/3rds of your maxHP boosters are played for a given win, so a 3-SoD pdials would have a factor of 1.24 (since you receive half as much electrum as you have extra maxhp). This is definitely open to discussion, and feel free to pretty much just guess at this factor if you're trying to figure out a deck of this sort. If you're the sort of person who sits around every game and makes sure that you stall until you get all the SoDs/stoneskins out, feel free to count all of them. Like I said, subjective. Also, totally irrelevant to basically everything except higher arena leagues, as the maxhp bonus is pretty irrelevant to everywhere else which gets nearly all its profit from spins. Also, totally irrelevant to about 95% of farming decks which never go above 100 hp.
Extra HP TL;DR: Extra HP Factor ("XHP") is a subjective number (until it gets tested, if ever) based on the average maxhp of a deck (and is calculated by way of 1 + (half extra average maxhp)).
Spin ProfitPut simply, spin profit is the profit you get from selling a won spun card multiplied by the rate of winning a spun card. This is also where we deal with the bonus five electrum from a match-2. To start with, the value from selling a won upped spun card is 1160 electrum, which is the value used by FGEI. The value for selling a won unupped card is 62 electrum per Xenocidus' simulation of the spins from 1.3 million AI3 games. In the absence of any way to get information about the value of unupped cards against arena/ai4, they will use the 62 electrum as well, since it's the best we've got. If anyone has suggestions on this front, please say so. The unupped spin value includes the bonus electrum from matched cards. I don't know if the upped spin value does, but when winning an upped card, the 5 electrum difference in spin value might as well be a rounding error.
Spin rate is 41.26% against AI3 per Xeno's simulation mentioned above. I find the general distribution of cards within decks in arena to be broadly similar to AI3, so I use this rate for all regular spins in AI3/arena. Due to the fluid nature of arena, I don't think a perfect number can be found, but I'd love to hear any suggestions if anyone has a better one to use for anything. Total spin profit for AI3/arena is 25.60.
AI4 spin chances are taken from actual tests in the AI4 study. At the time of
this post edit on 28-Jan-14, they are 9.08% for upped and 20.27% for unupped. Therefore, an AI4 win has a total spin profit of 117.90.
For the purposes of this formula, it is assumed that all won cards are sold.
Spin Profit TL;DR: Total Spin Profit ("TSP") is 25.60 for AI3/arena and 117.90 for AI4.
Special SpinsSpecial spins apply only to arena, obviously. For the sake of this study, it is assumed that all won rares are sold. The actual average value of all special-spin-able rares is 156.11 unupped and 1299.30 upped. Special spin success chance is
arbitrarily 75% assuming you play optimally. This is absolutely open for discussion, but it's what chat came up with a few months ago when I discussed it, and it sounds about right to me. I would love further opinions on it. is 73.92% per the optimal special spin algorithm study. Because of this, the value of each special spin is 115.40 unupped and 960.44 upped.
Special spin rate is calculated as a function of win rate and TTW. The easiest way is to just use the table from the OP of the arena stats thread, but the actual formula to determine turns per special spin is:
(TTW * ((WR^-1) + (WR^-1)^2 + (WR^-1)^3 + (WR^-1)^4 + (WR^-1)^5))
...for bronze. Truncate the formula after ^4 for silver, ^3 for gold, and ^2 for platinum. Once you have turns per special spin, dividing TPH by turns per special spin will give you special spins per hour. Special spins per hour times special spin success chance times special spin sell value will give you the total special spin value.
Special Spins TL;DR: Special Spins per Hour ("SSPH") = TPH / (TTW * Games/Spin). Games/Spin is taken from the table in the Arena Stats OP or from the formula above. Special Spin Value ("SSV") = 115.40 for unupped and 960.44 for upped.
So, here's the bare bones of the formula from above all in one place:
Turns Per Hour ("TPH") = 333
Win Rate ("WR") = Wins/(Wins + Losses)
Loss Rate ("LR") = 1 - WR
Turns Per Win ("TPW") = Turns To Win ("TTW") / WR
EM Rate ("EMR") = EMs / Wins
Win Value ("WV") = ((Stated Value ("SV") * 0.75 * (1 + (EMR * 1.67))) <arena/AI3> || ((SV * 0.6875) * (1 + EMR * 1.91)) <AI4>
Loss Value ("LV") = 15 <arena> || (0.5 * SV) <AI3/AI4>
Extra HP Factor ("XHP") = subjective. I like adding 1/3 of (potential max hp - 100).
Total Spin Profit Per Win ("TSP") = 25.60 <AI3/arena> || 117.90 <AI4>
Games Per Spin = ((WR^-1) + (WR^-1)^2 + (WR^-1)^3 + (WR^-1)^4 + (WR^-1)^5), truncated appropriately.
Special Spins Per Hour ("SSPH") = TPH / (TTW * Games/Spin)
Special Spin Value Per Win ("SSV") = 115.40 <unupped> || 960.44 <upped>
Wins Per Hour ("WPH") = TPH/TTW*WR
Losses Per Hour ("LPH") = TPH/TTW*LR
If we put all that together, we get:
(WPH * WV * XHP) - (LPH * LV) + (TSP * WPH) + (SSV * SSPH)
This is pretty much just another way of restating what I said at the beginning of the thread. The formula will be most useful if it is expressed purely in constants (per target) and WR/TTW/EMR, as those are the three stats that are tracked in most stats threads. So, if we expand out from that base formula, we get:
AI3:
((333/TTW*WR) * (SV * 0.75 * (1 + (EMR * 1.67))) * XHP) - ((333/(TTW/(1-WR))) * LV) + (TSP * (333/TTW*WR))
AI4:
((333/TTW*WR) * (SV * 0.6875 * (1 + (EMR * 1.91))) * XHP) - ((333/(TTW/(1-WR))) * LV) + (TSP * (333/TTW*WR))
Arena:
((333/TTW*WR) * (SV * 0.75 * (1 + (EMR * 1.67))) * XHP) - ((333/(TTW/(1-WR))) * LV) + (TSP * (333/TTW*WR)) + (SSV * (333/(TTW*GPS)))
...Which simplifies to the final formula:
AI3
(333 * WR * SV * 0.75 * (1 + (EMR * 1.67)) * XHP / TTW) - (333 * (1-WR) * LV / TTW) + (333 * TSP * WR / TTW)
AI4
(333 * WR * SV * 0.6875 * (1 + (EMR * 1.91)) * XHP / TTW) - (333 * (1-WR) * LV / TTW) + (333 * TSP * WR / TTW)
Arena
(333 * WR * SV * 0.75 * (1 + (EMR * 1.67)) * XHP / TTW) - (333 * (1-WR) * LV / TTW) + (333 * TSP * WR / TTW) + (333 * SSV / GPS / TTW)
For simplicity, here is all the values of the various constants, a reference table for GPS, and the third or fourth time I define the terms used:
WR means Win Rate (wins / games played)
TTW means Turns to Win (average)
EMR means EM Rate (EMs / wins)
SV means Stated Value (reward as shown in-game)
XHP means Extra HP (handles maxhp)
GPS means Games/Spin (see below)
LV means Loss Value (see below)
TSP means Total Spin Profit (see below)
SSV means Special Spin Value (see below)
AI3 AI4 Bronze Silver Gold Platinum
SV 20 40 ~15 ~60 ~115 ~240
LV 10 20 15 15 15 15
TSP 25.6 104.77 25.6 25.6 25.6 25.6
SSV 0 0 115.4 115.4 960.44 960.44
GPS Table:
Bronze (WR^-1) + (WR^-1)^2 + (WR^-1)^3 + (WR^-1)^4 + (WR^-1)^5
Silver (WR^-1) + (WR^-1)^2 + (WR^-1)^3 + (WR^-1)^4
Gold (WR^-1) + (WR^-1)^2 + (WR^-1)^3
Platinum (WR^-1) + (WR^-1)^2
Here are the formulas with the constants applied for the various targets:
Unsimplified:
AI3 (333 * WR * 20 * 0.75 * (1 + (EMR * 1.67)) * XHP / TTW) - (333 * (1-WR) * 10 / TTW) + (333 * 25.6 * WR / TTW)
AI4 (333 * WR * 40 * 0.6875 * (1 + (EMR * 1.91)) * XHP / TTW) - (333 * (1-WR) * 20 / TTW) + (333 * 117.9 * WR / TTW)
Bronze (333 * WR * 15 * 0.75 * (1 + (EMR * 1.67)) * XHP / TTW) - (333 * (1-WR) * 15 / TTW) + (333 * 25.6 * WR / TTW) + (333 * 115.4 / GPS / TTW)
Silver (333 * WR * 60 * 0.75 * (1 + (EMR * 1.67)) * XHP / TTW) - (333 * (1-WR) * 15 / TTW) + (333 * 25.6 * WR / TTW) + (333 * 115.4 / GPS / TTW)
Gold (333 * WR * 115 * 0.75 * (1 + (EMR * 1.67)) * XHP / TTW) - (333 * (1-WR) * 15 / TTW) + (333 * 25.6 * WR / TTW) + (333 * 960.44 / GPS / TTW)
Platinum (333 * WR * 240 * 0.75 * (1 + (EMR * 1.67)) * XHP / TTW) - (333 * (1-WR) * 15 / TTW) + (333 * 25.6 * WR / TTW) + (333 * 960.44 / GPS / TTW)
Simplified:
AI3 (4995 * WR * (1 + (EMR * 1.67)) * XHP / TTW) - (3330 * (1-WR) / TTW) + (8524.80 * WR / TTW)
AI4 (9157.5 * WR * (1 + (EMR * 1.91)) * XHP / TTW) - (6660 * (1-WR) / TTW) + (39260.7 * WR / TTW)
Bronze (3746.25 * WR * (1 + (EMR * 1.67)) * XHP / TTW) - (4995 * (1-WR) / TTW) + (8524.80 * WR / TTW) + (38428.2 / GPS / TTW)
Silver (14985 * WR * (1 + (EMR * 1.67)) * XHP / TTW) - (4995 * (1-WR) / TTW) + (8524.80 * WR / TTW) + (38428.2 / GPS / TTW)
Gold (28721.25 * WR * (1 + (EMR * 1.67)) * XHP / TTW) - (4995 * (1-WR) / TTW) + (8524.80 * WR / TTW) + (319826.52 / GPS / TTW)
Platinum (59940 * WR * (1 + (EMR * 1.67)) * XHP / TTW) - (4995 * (1-WR) / TTW) + (8524.80 * WR / TTW) + (319826.52 / GPS / TTW)
Note that, due to rounding, the simplified formula will produce slightly different results than the unsimplified formula. There are rounding errors all over the place already, so neither is really more "correct" than the other, and really due to the rounding errors, UEI is probably accurate to around the nearest hundred or so. Not that that will stop me from citing values to the hundredth of an electrum all the time. Note that all studies I manage use the simplified formula.
As I said at the beginning, I am posting this primarily because I would like some peer review. Please, let me know what you think. If you have suggestions on how better to handle any part of this, or if you have suggestions on better values for constants, or if you found a typo, or if you found a fundamental flaw in my understanding of math, please, let me know. I would like as much input about this as I can get. Also, I wrote this more or less in a sitting, so it is
very possible I made some error somewhere while transcribing everything. Please tell me if you find any. I will likely be updating this post in the near future.
A big thank you to everyone who has done anything that I drew from here, and a big thank you to anyone who actually managed to make it all the way through this enormous amount of stuff.
Bibliography:
edit: Corrected game->win in first formula per rob's comment.
edit2: Added bibliography.
edit3: Corrected TTW->TPW error in special spin formula per my comment below.
edit4: Corrected TTW->TPW error in wins/hour formula per my comment below. Ugh.
edit5: Corrected misplaced XHP modifier. Also cleaned up most of the formulae so they are hopefully more readable. Added GPS table.
edit6: Fixed XHP error for now.
edit7: Clarified SSV
edit8: Major update. See
hereedit9: Fixed typo in EM factor in unsimplified formula for arena decks.
edit10: Fixed incorrect EM factor and added details regarding UEI(333) and UEI(250).