Hi everyone! Boy, do I have a treat for you guys this week! Micah, from JankJunction, has collected over 1000 deck lists and corresponding win rate submissions. If you aren’t already doing it, I would strongly recommend submitting your draft decks here. For today’s article, I will be talking about how to interpret the results of the GLM analysis I did and go over some of the more interesting results. Of course, I couldn’t have done this without the awesome help from Micah so we decided to do a co-opt article and Part II of this article will be posted over at JankJunction!
As a prelude, I do know that there are definitely submission biases present in the data set. However, by running a regression based model, most of the submission bias should be removed. Some residual bias (especially the skew towards 7-wins) will not be completely accounted for, but that should only adjust the absolute values obtained, but not the relative values. So for example, Praxis Displacer might not be exactly at +6.42 WR modifier, but it will definitely still have the highes WR modifier. If you are interested in the actual analysis itself, I’ve also included a simplified explanation in the postscript at the end of the article. Also, feel free to poke me in the reddit thread for more in-depth stats discussion!
Interpreting the Results!
If you want to check out the raw data, its posted here and also available at JankJunction’s spreadsheet. The first two columns are pretty self-explanatory and the third column is the WR modifier that I generated using my model. The last column is a 95% Confidence Interval measure, giving the +/- range in which 95% of the true WR modifier falls. This WR modifier measures how including that specific card alters the estimated win rate of the deck. So for example, adding a Praxis Displacer to your deck would increase your deck’s predicted win rate by 6.42% while adding a Infinite Hourglass to your deck decreases it’s predicted win rate by 5.92%. So, at the first level, it seems big positive WR modifiers means the cards are good to include and big negative WR modifiers means the card probably should not be in your deck.
However, because you don’t get to choose from all the cards available in the game (who would play such a format anyway?), there is an element of player rating bias. When certain cards are overrated and included in the draft deck over better cards, it drags the WR modifier of the included card down (even if the included card is not THAT bad to begin with). Moreover, certain “trap” cards (e.g. Katra, the Devoted, Slimespitter Slug) can cause players to force a faction pairing that isn’t open and hence, these cards will also end up lower on the WR modifier scale despite being good cards in their own right.
This means that the WR modifier not only indicates the absolute strength of the card, but also both how overrated/underrated it is, and it’s “trap” potential. For example, Tinker being at +1.5 WR Modifier does not mean that it is a stronger card than Roosting Owl at -0.6 WR Modifier. Instead, this could be an indication that people tend to underrate Tinker. People might also overvalue Roosting Owl and end up forcing Justice after a p1p1 Roosting Owl.
15 Most Commonly Played Cards
|15 Most Commonly Played Cards||Times Played||WR modifier|
Flash: Well, it is unsurprising that the top 15 most played cards consist almost solely of Fire, Time and Primal cards. After all, these factions are also the most represented in the data set (see the faction tab here). That being said, it is definitely eye-catching that both Gun Down and Dragonbreath have a significant negative WR modifier on the deck. This signals to me that people are picking and playing too many clunky removal (high cost for Gun Down, exhaust effect for Dragonbreath) in their deck over good units. While removal is generally good, spending your entire turn to remove a single enemy unit without developing the board isn’t always ideal. Personally, I run at most 2 Dragonbreath in any Primal deck, and a maximum of 4 high cost removal (Mortar, Gun Down, Magma Javelin, etc).
Another interesting note is that the three core Strangers for Fire, Time, Primal all have low positive or negative WR modifier. I think that this effect arises because those 3 factions have some of the strongest 2-drops (Sand Viper, Nobel Firemane, Blinkwolf, Bold Adventurer) and these Strangers has to compete against them for the slots. Thus, if you are running multiple Strangers in your deck, you are probably missing these 2 drops and hence, not having as strong a deck.
Cannonbearer, Archive Curator and Sand Viper all have positive WR modifier, indicating that they are indeed THAT good to justify being a first pick. Stormcrasher, another common first pick, has a negative WR modifier, suggesting that it is not actually as strong as the player base thinks. A contributory factor to this low modifier could be that Stormcrasher actually does not play well from behind. Having a below-curve attack and health means it can’t really block or race well (unless the ground is locked up).
Sneaking in at 15th place, with a shockingly high WR modifier of 4.4, is one of my favorite cards, Jotun Cyclops. I definitely think this card is WAY underrated and the stats back me up to this. In a world where 2 drops are mostly 2/2s, being a 4/3 is not significantly worse than a 4/4 Striped Araktodon, which is already a very good pick. Moreover, Jotun Cyclops has 2 powerful lines of text. Getting a free snowball is excellent (see Jotun Hurler) and the overwhelm helps to proc future sparks even if the opponent throws a 3/3 to trade for your 4/3.
Micah: By far the most interesting thing about the 15 most played cards is how many of them have a marginal net positive or even negative WR modifier. Praxis Stranger, Elysian Stranger, Stormcrasher, Pteriax Hatchling, Dragonbreath, Gun Down, Skycrag Stranger, Striped Araktodon, Mortar and Canonbearer. That is a who’s who of cards you typically see in a standard Praxlysian deck. What that tells me is that these cards, and in general those three factions, are highly overdrafted/overrated. Because splashing is so effortless in time based decks, players are able to assemble competent, but not great decks. Dragonbreath and Gun Down might just actually be too much of a tempo loss to be actively “good”. If you’re in these factions and those two spells were all you could find for removal, you might have overlooked a powerful Shadow or Justice based deck.
*One important thing to note with Purify is that the data represented here was all collected before the recent change.
15 “Best” Common Cards
|15 “Best” Common Cards||Times Played||WR modifier|
Flash: This is a pretty diverse list, with representations from all 5 factions! There are a few surprises on this list, but overall, I do agree with most of the cards been present here, either due to being underrated or just based off pure card power.
Micah: There are definitely some surprises in this list. Perhaps the most surprising is the number of shadow cards present. A full 1/3rd of the list are Shadow cards! There’s a theme to this list of cards. Can you spot it? Let’s go through the list card by card and see if we can discover it.
1. Synchronized Strike
Flash: If I had to guess the best common, I would never have guessed Synchronized Strike in a million years. As a rationalization (note: not explanation), part of the power of Synchronized Strike arises because Time has a significant and wide array of fast spells (Teleport, Refresh, Synchronized Strike, Bolster). This makes blocking around tricks extremely difficult and sometimes, you could end up blocking around Bolster, only to get blown out by Synchronized Strike. Being a generally undervalued trick should also increase the surprise factor and chances of blowout.
Micah: This card did not surprise me as it had one of the highest win rates of any of the commons in the dataset. In fact all but 2 (Yeti Spy and Pilfer) commons with win rates higher than 69% also showed greater than +2 WRM. This is a combat trick for your entire board, which when played at the right moment is almost always a 2-for-1 or better.
2. Dark Return
Flash: Dark Return being at rank 2 is not surprising to me. Isomorphic has completely sold me on this card. Despite being slightly lackluster in your opening hand, it can always do work at any point in your curve, similar to how the old Copper Conduit functioned. Moreover, the ability to recur your biggest threats and the synergy with killer and echo pushes this card’s impact up significantly.
Micah: Dark Return has always been good especially with echo units. The card has always read, “Draw your best unit that has died this turn and give it +1/+1″.
Flash: I’m very happy to see Devour up in the ranks as well because in my opinion, it has been unjustly underrated for a very long time. While it first appears as a simple tempo-negative cycle (since it costs 2 cards to draw 2 cards), it is rarely a simple 2-for-2. You can often wait for a fast spell or removal from your opponent and devour in response, making it a 3-for-2. For some revenge/entomb effects, you can also devour in response to a silence, negating the silence and triggering the entomb. Moreover, similar to the argument for Direwood Prowler, you often have a random 2/2 Stranger lying around in board stalls, so being able to “cycle” it is great.
Micah: Devour increased in value with Set 2 due to lifeforce and revenge. As anyone who has played enough constructed can tell you, having your opponent Devour a revenge unit and then immediately draw it is incredibly frustrating. Set 2 also introduced more board stalls into the format and sacrificing your weakest unit to dig deeper for a way to break the board is an advantage that can’t be overlooked.
4. Xenan Destroyer
Flash: Xenan Destroyer is pretty average and it is surprising to see it so highly ranked. A main contributing factor could be that it is often played alongside synergistic cards. As someone who has been overrun way too often by Xenan Destroyer with Blackguard Sidearm, I can safely attest to that being the stuff of nightmares.
Micah: This guy is still as ripped as ever and he becomes much better with lifeforce in the format.
5. East-Wind Herald
Flash: East-Wind Herald being this high is a little, but not very, surprising. It has definitely gotten stronger with the release of Set 2, specifically the Spark mechanic. There are very few 2 or 3 power fliers, so a turn 2 East-Wind Herald is almost guaranteed to be able to spark your 3-drops, such as Clan Hero and Crafty Yeti. Fliers in general have also gotten stronger due to board stalls being more common, giving East-Wind Herald a further bump.
Micah: As it turns out in a format full of 2/2’s, a 1/3 flier is pretty solid. The fact that it can usually enable Spark whenever it likes makes this probably the best spark enabler in the game. Also quick, which flying units can this little elemental not block?
6. Horned Vorlunk
Flash: Horned Vorlunk is the definition of average for me and I think being underrated by the general draft population is a big contributing factor to this large modifier. Similar to Xenan Destroyer, I think Horned Vorlunk also benefits from being drafted and played due to synergistic considerations. If I ever open 2 Ageless Mentors, you can bet I will snap up every Horned Vorlunk I see.
Micah: The fact that this has such a large modifier is the surprise for me here. Before Flash’s analysis I would have gladly taken an Awakened Sentinel over this (I realize they don’t exist in the same packs). But you really do get a solid unit here. It’s easy to cast, has pseudo evasion and 4 health lets its really slow down your opponent’s aggressive starts.
7. Jotun Cyclops
Flash: Well, what can I say besides “I told you so!”. Also, a huge shout out to Neon and Sir Rhino’s podcast that convinced me to pick Jotun Cyclops more highly. Playing with it definitely sold me on the card’s strengths.
Micah: Ah, here we have our first card that doesn’t fit the theme of the list so far. Much like Horned Vorlunk, I knew Cyclops was good, but I didn’t realize it had this much of an affect on the win rate. When you are able to spark it, you are essentially drawing a free, slightly worse temper. That is actually really strong. The added evasion in the form of overwhelm plays really well with Skycrag and Hooru’s aggressive tempo based game plans.
8. Valkyrie Aspirant
Flash: Just like East-Wind Herald, I think Valkyrie Aspirant received a significant bump for being solid fliers. I also think Valkyrie Aspirant has a net benefit because it appears lackluster to newer players. However, it is actually a great power sink for late game, and being recognized as such by the top ranked drafters also inflated it’s modifier.
Micah: Who knew a 1/1 flier that can later become a 5/5 flier is great? In retrospect it should be obvious how good this card was, but I routinely passed it over.
9. Hooru Fledgling
Flash: This card ties in nicely with the fliers matter theme that this list has shown and a 3/3 for 5 flier is nothing to scoff at. However, I am surprised that this card received a higher WR modifier than Valkyrie Denouncer. This leads me to hypothesize that drafters are generally too loose and greedy with their splash.
Micah: This little owl has always had a special place in my heart. 3/3 flier for 5 is not a great rate to pay, but it also is one of the few commons that Justice gets that has decent stats in the air. This also blocks all the same fliers that East-Wind Herald does, it just happens to kill most of them as well.
Flash: 3 damage for 1 power? Who would’ve thought this card was good? (kappa)
Micah: I don’t think anyone is surprised to find this here. Although it is slightly less powerful than in Magic: The Gathering, 3 damage to a unit or player is still an incredible rate for 1 power. I would say this got slightly better with the addition of Set 2 due to the power of Skycrag and Praxis, not to mention the weaker units added to the format.
Flash: I don’t think Icebow is that great on average, but it is definitely a high variance card. In decks where it is good, it is sickeningly good while in decks where it is bad, it is really pretty bad. This means that the card only sees play in synergistic decks, thus bumping it’s modifier up. Icebow does crazy shenanigans with infiltrate units (Direwood Beastcaller, Memory Dredger, Argenport Ringmaster) and deadly units (Sand Viper, Blistering Wasp, Lumen Defender). A special mention goes to Gorgon Swiftblade, that works great with Icebow regardless of whether it has infiltrated or not.
Micah: This is really the only card I’m REALLY scratching my head over. I do have a theory though and it’s something we’ll be talking about more in tomorrow’s article at JankJunction and that is how powerful it is for a card to have multiple effects. In this case, it pumps a unit and has a ping effect attached. Additionally it can sometimes be used to enable Spark. All of these things in addition to it likely being underrated add up to it our 11th best common.
12. Iceknuckle Jotun
Flash: Iceknuckle Jotun is another unexpected guest in the top 15 list, and I suspect that having 6 health is a huge contributory factor. With the dilution of hard removal spells due to the addition of Set 2, having 6 health means that it rarely gets removed efficiently. It is able to stall out the ground very well and often gets a 2-for-1 trade if your opponent wants to push through.
Micah: I know this one looks odd at first, but most units with an effect stapled to it are stronger than they first look. The other important factor here is the 6 health. ALL units with 6 health and less than 8 cost (except Horngrinder) have a positive WR modifier.
13. Cabal Slasher
Flash: Cabal Slasher is definitely bad in my opinion, but I guess not as bad as I first expected. Even in lifeforce decks, I would not be overly happy to run this but perhaps there is some underplayed lifeforce aggro that I am not aware of. It might be worth a second look but I do think that it is just a severe underrating that inflates its WR modifier.
Micah: Another surprise here, but in a deck with any way to consistently gain life this is often a Clan Hero or Pit Fighter (2.0 and 3.2 WRM respectively). Three toughness lets it block strangers for days, which can give you time to find your Lifeforce enablers. I think this card is definitely underrated which is boosting its WR modifier slightly.
Flash: Extract is arguably the best shadow common in set 2 so seeing it this high up isn’t the biggest surprise. I also think Extract reaps a lot of benefit from not being as shiny and eye-catching as the other good shadow cards (e.g. Slimespitter Slug, Memory Dredger) and hence, it only gets played when shadow is actually open.
Micah: I’m not surprised Extract is is in a list of very good cards, I am surprised it’s “better” than Purify. Again this is another card that has multiple effects. 3 damage, 3 life and a scry (looking at the top card of your deck and putting it on the top or bottom) is quite the package for 3 power. Extract is also not a card you can splash. That may seem like a negative, but there is a real cost to splashing a third faction. If you notice we haven’t yet had a multi-faction card in the top 14 best commons.
15. Crownwatch Deserter
Flash: Crownwatch Deserter is a solid card. 3/3 for 3 is the standard rate and warcry is definitely a great snowball mechanic. I do agree with Micah that this rating might be slightly high due to Rakano being underrated as a faction.
Micah: Our first multi-faction card! 3/3 for 3 is an excellent rate in a world full of strangers. Everyone knows that warcry is great, especially for breaking boardstalls. Eventually you’ll draw that +3/+3 unit and the game will be over. I think this is also seeing a small underrating due to Rakano being perceived as a weaker faction-pair in the new format.
Micah: So what is the main theme of these 15 commons? The Empty Throne is totally over powered! Only 1 Set 2 card in the top 10 is pretty striking and lines up with what we’ve seen in the constructed format. If this pattern holds for the uncommon cards as well, there is a strong case to be made for not settling into a faction pair until your first Throne pack (Pack 2).
For Set 3 drafts, we should also look out for cards that have multiple effects stapled to them. These cards will probably exceed the community’s initial expectations, which can give you an edge in the early days of the new format. One last thing to consider is the cost of splashing into 3+ factions. I myself have been guilty of drinking the multi-faction kool-aid and I’ve had many 7-win drafts as a result. However it’s possible, I’ve been splashing too often for cards that have too little an impact on my decks.
Flash: As Micah pointed out, the list is pretty much dominated by Set 1 cards. Besides Set 1 cards being of a higher power level, another contributing factor could be the 2-1-2-1 pack order. These results suggest that players might settle into a faction way too early and end up forcing a faction pairing that just isn’t open in packs 2 and 4. Single faction cards also make up 14/15 of this list and I do suspect this is an indication that straight up 2F decks are stronger (since the proportion of single faction cards should theoretically go down as the number of factions/splash increases).
15 “Worst” Common Cards
|15 “Worst” Common Cards||Times Played||WR modifier|
|Initiate of the Sands||62||-4.72|
Micah: The bottom 15 have way less surprises than the top 15, but there are still some interesting results here. We have a much more even split between the Empty Throne and the Omens of the Past cards.
1. Predator’s Instinct
Micah: It turns out picking a Predator’s Instinct is often incorrect! This being the worst common by a large margin was definitely a surprise, especially given that Xenan Initiation is one of the best uncommons. At best, this is one of your large units taking a turn off from swinging to kill a small unit. At worst you are 2-for-1ing yourself. This will occasionally still be playable and I’d like to see someone try to stop me taking this card after I’ve picked up 1 or 2 Snapping Brushstalkers. However, there are probably better options available to you.
Flash: This is definitely a surprise initially, but it started to make sense with some further thought. Arguably, Predator’s Instinct is just a worse Xenan Initiation. Thus, while not being a bad card on it’s own, having Predator’s Instinct in your deck often means you’re not running Xenan Initiation, which in turn means your deck quality is often lower. This negative impact of better replacement cards is an inherent weakness of the model because we don’t have access to the entire pool of 48 cards that was used to construct this deck. We also see similar effects for cases such as: Strength of Many (a worse Finest Hour), Storm Glider (a worse Stormcrasher) and Scaly Gruan (a worse East-Wind Herald).
2. Longshot Marksman
Micah: This is not surprising in the least. It can be scary in a deck full of weapons, but on the whole this is still going to trade for a stranger once the opponent can double block, and it gets completely stopped by an Awakened Sentinel. Being in a poorer performing faction does it no favors either.
Flash: Quickdraw is scary, but a 2/1 gets outclassed rapidly in my experience. Moreover, 1 health makes it vulnerable to snowballs and ping effects, and quickdraw alone is not sufficient to compensate.
3. Xenan Cupbearer
Micah: Lifeforce can be good, but if your plan to enable it is to swing with a 2/4 lifesteal in a format full of 2/2 fixing strangers, I’ve got some bad news for you.
Flash: A over-costed unit: Check. In a under-performing faction: Check. Picked over better cards in order to try and force a archtype (lifeforce): Check. Given this list, I think there is no question as to whether Cupbearer belongs here.
4. Trail Runner
Micah: The charge on this unit is just flavor text for the most part, which means this is a 2 power 1/3. This is much worse than a 2/2 or 2/3 because while it can block, its almost never trading with anything besides a Blinkwolf.
Flash: 1/3 as a body isn’t significantly worse than a random 2/2 stranger in my opinion but I think the glut of good 2-drops in general (Awakened Student, Bold Adventurer, East-Wind Herald, Blinkwolf) pushes the WR modifier of generic 2/2s down. We shall see the same effect in future cards as well.
5. Copperhall Recruit
Micah: You will often hear Mann_Und_Mouse extol this cards virtues, but unless you are a top 100 Masters drafter you should steer clear. If this was a 2/6 it would probably be in the top 15, but as it is, you should try to avoid playing this card except in very specific decks.
Flash: I’m surprised to learn Mann_Und_Mouse loves this card, but I guess even legends can have momentary lapses in judgement! 2/5 is a good defensive body, but nothing to write home about. I would play it if i need to stall up the ground in hooru, but otherwise, it just isn’t worth a card slot in my opinion.
6. Initiate of the Sands
Micah: Another big surprise here. I was not a fan of Initiate to begin with, but I didn’t expect it to be one of the “worst” cards. This is mostly only good on turns 1 or 2, and the rest of the time it’s outclassed by everything.
Flash: I am totally surprised to find this card here. It is a very good card and has definitely performed well in my experience. It replaces a sigil so it doesn’t dilute your good topdecks late game while giving you the potential to play out your bigger units faster and earlier. A possible explanation would be the increase in 3F/4F greed piles, which makes Initiate strictly worse than a sigil since you will often end up influence restricted rather than power restricted.
7. Combrei Stranger
Micah: It’s hard to say what makes Combrei Stranger so much worse than the other fixing strangers. This probably has to do with the best Combrei cards wanting to be played on turn 2 (aka Awakened Student). Another factor could be that most of the Justice bombs have pretty heavy influence requirements, which would make them hard to splash.
Flash: A word of caution, I think that the WR modifier estimates for Strangers and Banners are very imperfect. This is because it strongly violates the assumption of the card being equally good in all decks. A Combrei Stranger would be significantly better in a Combrei-based deck, while just a vanilla 2/2 in a Feln deck. Given that, a better way to classify the strangers will perhaps be fully on-faction, half on-faction and completely off-faction. This will take a fair bit more work though, but definitely something to look into for future analysis.
8. Civic Peacekeeper
Micah: This card is really a 7 drop and like all 7 drops, must reach a very high bar to be playable. A 3/3 with upside if you flood out is not where you want to be in this format. I think it’s playable with the right game plan, but that is probably 10% of the decks that do end up playing this card.
Flash: 6 power 3/3 is not what you want to see, regardless of your board state. This is basically a broke man’s Eye of Winter that costs a power to activate AND dies to torch. I’m not sure how much worse this card can actually be.
9. Scaly Gruan
Micah: See Trail Runner above. I like my blockers to be able to kill things in double block situations. This doesn’t pass that bar and you should not be playing it often.
Flash: Also, see Trail Runner. Being nearly a strictly worse East-Wind Herald is not doing it’s rating any favors.
10. Xenan Stranger
Micah: Similar to Combrei Stranger, Xenan Stranger competes with the good Justice and Shadow 2-drops.
11. Elysian Banner
Micah: I’m not sure what to make of this. I will add that 6 of the banners have negative WR modifiers and 4 of those (Elysian, Praxis, Argenport, and Xenan) have -2 or lower WR modifiers.
Flash: While I think it is next to impossible to draw any conclusion regarding Strangers, I do think Banners are slightly more informative. Banners only see play if they are either your 2 base factions, or a combination of your splashed faction and your base faction. Assuming a 2F+splash deck, there are 2 Banners that include the splash and 1 Banner that doesn’t. As such, it is inaccurate, but reasonable to think about the Banners as indicators of the splash. All 4 Time Banners (Elysian, Praxis, Xenan, Combrei) have negative WR modifiers and I think this indicates Time as being the worse faction to have on the splash. Coincidentally, this is also backed up by my own records when I have the lowest win rate with Time as a splash.
12. Sauropod Wrangler
Micah: Playing a Vanilla 2/2 that can conditionally ramp you is not going to win you games in this format.
Flash: Sauropod Wrangler is almost never better than a half on-faction stranger, and this stats agree with my evaluation. It’s hard to draft multiple hits for Sauropod Wrangler and in a world of 2/2s, Sauropod Wrangler often ends up having to trade for an opposing 2/2.
13. Lethrai Ranger
Micah: I’m saddened by Lethrai Ranger’s appearance here, but not surprised. The rise of fixing strangers sealed her fate.
Flash: I am actually relatively surprised to see Lethrai Ranger here. It may no longer be as good as it was in Set 1, but put a Blackguard Sidearm on this card and it can still easily take over a game. I would guess that this negative WR modifier is a case of the community overrating her due to her powers back in pure Set 1 draft.
14. Highbranch Sentry
Micah: Phrases like “best Justice common” have been tossed at this 3/3 for 3, but sadly it does not appear to be true. It does have upside, but requires another card and a loss of tempo to realize that potential.
Flash: This is another shocker for me since i always thought 3/3 for 3 is a good rate. However, it seems the lackluster text holds it back significantly compared it’s fellow Justice 3 drop (Brightmace Paladin at +1.26 WR modifier).
15. Disciplined Amanera
Micah: 2/2 for 3 is almost never an acceptable rate. I MIGHT play this if I managed to snag 3-4 Sanctuary Priests.
Flash: The only surprise for me here is that more lifeforce cards are not present in the bottom 15. 3 power 2/2 is just flat out bad, and it requires at least 2 triggers to be better than your average 3 drop. Hitting multiple triggers consistently in your early game is going to be extremely rare, and hence unlikely to outweigh to risk playing a sub-par cards.
Flash: Well, this list definitely had less surprises for me than the 15 best commons. In general, it seems that cards that have almost strictly better “replacements” tend to end up here.
Micah: The key themes for the worst commons seem to be cards that have only 1 effect, cards that are overcosted, or cards that are very narrow. That sounds about right to me!
Well, that wraps up the discussion for Part 1, but don’t forget to check out JankJunction for Part 2 where we discuss the best and worst uncommons! Part 3 and 4 will also be soon to follow so keep your eyes peeled for that! I hope you enjoyed this large data set and analysis we’ve done and let us know your thoughts in the reddit thread!
In Statistics We Trust,
P.S. The GLM Analysis
I am currently working as a fMRI physicist (the kind that sticks people into giant magnets and scan their brains) and one common analysis method that we use to process our data is the General Linear Model. As the saying goes, “if all you have is a hammer, everything looks like a nail” and I realized that this was a good way to extract out the impact of each card in draft.
For this analysis, I’m assuming that regardless of deck and player, playing a certain card will alter the deck’s win rate by the same amount. Of course, this is not true, but given a large enough dataset, it’s a reasonable assumption. As such, I can write out each deck in equation form. For example, if deck 1 has a 0.6 win rate and contains Cards A,B,C,D
0.6 = WRA+WRB+WRC+WRD
where WRA is the WR modifier of card A. Now, for another deck, I can write out a similar equation depending on what cards it has, so maybe something like
Deck 2 Win rate = WRA+WRC+WRD+WRE
Now, with enough samples, I can create a whole list of such equations and solve them simultaneously to obtain an estimate for the WR modifier of each card. This raw estimate is then regularized and weighted by the number of samples (to effectively account for the uncertainty in the estimates) to give the WR modifier that you see in the table.