Hearthstone Learning Mindset and Data-Driven Deckbuilding

Hearthstone Learning Mindset and Data-Driven Deckbuilding

Table of Contents

• Lesson 1: The Learning Mindset
• Lesson 2: What is the game of Hearthstone about?
• Lesson 3: The Resources of Hearthstone
• Lesson 4: Interaction And The Clock
• Lesson 5: Deck Building and the Importance of Data
• Lesson 6: The Mulligan Phase
• Lesson 7: The Skill Cap
• Lesson 8: Tilt
• Concluding Thoughts
• Understanding and Interpreting Hearthstone Statistics

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Lesson 1: The Learning Mindset

“The first principle is that you must not fool yourself — and you are the easiest person to fool.”

-Richard Feynman

My name is J_Alexander, and this is a guide for everyone who plays Hearthstone. From the novice through to the expert, many of the same principles will help us continuously improve in the game and have a better time playing. So long as you have things you’re trying to achieve in the game - whatever they are - getting better at understanding the game will help you achieve what you set out to do more regularly.

I want to begin these lessons with the point that we are all humans. Inside our heads are very human brains, evolved over our history as a species for solving a great many problems. Most of the problems you will face when playing Hearthstone are not those same ones. Because we did not evolve to solve these particular problems, our brains will be doing the best job they can with the tools we have available, but the fit will often be tenuous. We do not possess the right mental tools for the job.

Because of this mismatch between the task and our tools, we are going to mess it up. It’s not a matter of “if” we will; it’s simply a matter of “how much” and “how often”. This is true of novice players and pros alike. Even the best players make mistakes regularly.

I tell you this because the first step in improving and learning - no matter your current level of performance - is truly internalizing you always have things to learn and are making mistakes. If you don’t take personal responsibility for all your game experiences and think it’s outside of your control, you’re already failing the first and most important step.

Figuring out what we need to learn and improve is hard, largely because we’re often blind to the mistakes we are making. You don’t know what you don’t know, which makes it challenging to figure out where to even start.

Making matters complicated is that your mind will fight you when it comes to self-improvement. Admitting fault is difficult and can be embarrassing, especially if you got angry or stated an opinion publicly. We will provide plausible-sounding excuses for our failings.We will argue in favor of things we wish were true. Unfortunately, making excuses, instinctual as it might be, will interfere with our ability to get it right next time, and you will do this without even being aware you are doing it.

No doubt some of you are reading all this and thinking, “I don’t know why I should care, since I only play the game for fun and don’t care about maximizing my win rate.” You don’t want to turn your video game into your video job. However, I think the exact opposite is true: if you adopt a learning mindset and seek to improve your understanding of the game, you will actually come to enjoy your time playing more. When you understand your experiences are under your control and know how to control them better, you will find there are all manner of nuances to the game you never noticed before, and come to appreciate them in ways you wouldn’t have expected.

You may even have fun improving. The better you are at understanding the game, the more freedom you have to play it on your own terms. If you play to win, improving will help you do that. If you play to build your own decks and find things other people have overlooked, improving will help you do that too. Whatever you want to do in the game, knowing more about the game can help you get there.

Refusing to improve can also directly lead to you having a bad time you don’t need to have. If you are blaming the game for your losses, rather than yourself, you will say that the game sucks. And what do you do with games that suck? You stop playing them. Being unwilling to improve can rob you of all the potential enjoyment you could have received from the game. .

Getting better won’t always be easy, but you will always have something to improve. Flawless performance will be impossible to achieve, so that should never be your goal. Instead, focus on getting that little bit better each day. Some days you will learn a lot, and others you may learn only a little. However much or little you improve, you cannot be afraid of being wrong. You’re human, and it’s going to happen to you whether you like it or not.

Lesson 2: What is the game of Hearthstone about?

To better understand anything, you want to understand its function. Knowing the function of a device helps you intuitively grasp its component parts, the interactions between them, predict the presence of pieces you didn’t yet observe, and helps you think about how the device might be used to achieve its goal.

For example, take a look at the tool pictured below. It might seem confusing at first glance. If you were handed this and told to do something with it, you’d probably spend a lot of time fumbling around and trying to use it to do things it wasn’t designed for. As a result, you’d end up doing those things poorly and wasting your time.

Now, if I told you this device was designed to peel, slice, and core an apple, it begins to make a lot more sense. That one piece of information allows you to organize your understanding and guide your efforts in a much more effective manner. You can quickly recognize that the spikes at the left end are designed to hold the apple in place, the crank used to rotate and move the apple forward, and you could even predict the presence of three blades that might not be immediately visible: one to peel the skin off, one to slice the apple, and one to cut through the middle and remove the core.

By knowing this device is an apple peeler, you also learn about what it won’t be good at. It might be decent at peeling a pear or an onion, but it works less well than it would with an apple. You learn that it won’t help open an egg at all and will certainly fail to cook your food. It will do poorly at playing music or transporting you to where you need to be. If you try to use this device for things other than its intended purpose, you will encounter failure and frustration. The further you stray from that intended purpose, the more of both you get.

Knowledge of what the game of Hearthstone is “for” - what goal you are trying to achieve when you play - is similarly useful for guiding and organizing your learning. Once you know what the game is about, that piece of information can help you learn what you need to learn: everything from your understanding of which decks are good and bad, which plays are better or worse, which card choices are powerful or weak, how you could improve your deck building, and beyond. So what is the game of Hearthstone about?

On the broadest level, Hearthstone is about reducing your opponent’s life total to 0 or less before they do the same to you. That is the one rule which defines what it means to win or lose a game of Hearthstone. This may seem like a point so glaringly obvious that it doesn’t need stating but - like our apple peeler - the implications of this bit of information are far broader than they might initially appear. Because it’s the rule that defines winning, everything else that happens in the game flows from it and needs to be understood in that light.

Many players get caught up on other beliefs about what they think the game of Hearthstone is - or should be - about. When players think Hearthstone is about something else, they start playing poorly: they pursue things that don’t make them win the game, lose games more often than they need to, and then get frustrated. They’re putting eggs into their metaphorical apple peeler and getting upset when they make a mess.

In order to get better at the game, you must ensure you truly understand what the game is about: reduce the opponent’s life total to 0. This rule applies to every player, every deck, every game, and every play.

To give you a sense as for how players may lose track of what Hearthstone is about, here are a few examples I’ve seen of incorrect answers players have provided (usually implicitly, but sometimes explicitly) to the question of what the game is about. Each of these beliefs will get in the way of their improving at the game:

• Hearthstone is a game about playing a unique deck that you’ve come up with on your own.
• Hearthstone is a game about saving your cards for the exact right moment to achieve their maximum potential.
• Hearthstone is a game about ensuring you remove all your opponent’s minions.
• Hearthstone is a game about outlasting every resource in the opponent’s deck.
• Hearthstone is a game about directly countering your opponent’s strategy.
• Hearthstone is a game about executing the most complex strategy.
• Hearthstone is a game about playing “honest” decks and not pursuing “cheap” strategies.

If you’ve ever heard someone talk about how they “won’t play brainless aggro decks” as if it were some point of pride, you have met someone who is playing by imaginary rules. They have lost sight of what the game is about. They think it’s a game about showing off how clever they are. Because being clever (or thinking you’re clever) does not itself reduce the opponent’s life to 0 or less, they will be rewarded for their belief with losses and their ability to learn about the game effectively will be reduced.

These incorrect perceptions about what the game of Hearthstone is about can be so insidious because players laboring under them aren’t aware of it. Despite their not explicitly believing that the game is about, say, removing all their opponent’s minions, their behavior will conform to that made-up rule all the same. They will begin each turn by thinking about how they have to remove their opponent’s minions and will do things they don’t need to which do not assist them well in reducing the opponent’s life total to 0 or less.

In other words, these incorrect beliefs can give you tunnel vision. You will focus on the wrong things and fail to see the correct course of action.

Now there’s nothing wrong with you if you want to pursue other goals because it adds enjoyment to your time playing the game, but you should go into it with both eyes open and understand what you’re doing. They are self-imposed restrictions. They do not define winning in the game, they will not assist you in winning games, your opponent knows nothing about them, and they’re not under any obligation to play the game by your personal rules.

Once you fully and consistently grasp the idea that Hearthstone is a game about reducing the opponent’s life total to 0 or less (since that’s what defines winning), you can more effectively organize your learning and begin to focus on the specifics of improving your play. You can set up any boundary conditions under which you achieve that goal (for instance, I primarily play Rogue because it’s more fun for me), but your primary goal is always the same: kill the opponent.

Lesson 3: The Resources of Hearthstone

Now that we know what Hearthstone is about, we can begin to use that to better understand the specifics of how we achieve our goals. After all, that goal of reducing the opponent’s life total to 0 is suitably broad and the details of how we get there are vague.

Beginning again with some framework that helps guide our learning, we win through the utilization of the limited resources we have access to during the game. There are a variety of these, including the cards you draw, the minions you put into play, the number of actions you can take during your turn, your hero power button, the mana you gain each turn, the cards you generate, your life total, the number of cards in a deck, and the number of turns a game allows. Each of these resources can be used and traded-off to help reduce the opponent to 0.

When I say resources are limited, this means every time you use a resource on one goal, you cannot use it on another. An attack used on a minion is an attack not used on the opposing hero. Mana spent on playing a minion is mana not spent playing a spell. Cards used to draw are cards not used to develop your board.

If you commit too many resources to goals that don’t win the game by reducing opposing life totals, even if you achieve those goals efficiently, you open an opportunity for your opponent to do the things that actually win.

Think of it like this: each turn you don’t kill your opponent, you are giving them access to more cards, more mana, more actions, and more time to kill you. If you don’t win on turn 1, your opponent has 1 more mana and 1 more card draw to work with at minimum. If you don’t win on 10, your opponent now has 10 more mana, 1 more card draw, whatever minion attacks they can make on board, and another use of their hero power at minimum. Each time you don’t focus on winning the game, you give your opponent that much more opportunity to do so, and that many more resources to do it with.

This means if you want to get more out of your resources than your opponent, make sure your opponent doesn’t have access to additional turns because they already lost. Destroying their minions on board might feel nice, but if you destroy their life total you also destroy their minions on board, and their hand, and their hero power, and their deck. If you stop them from being alive, you stop them from using their resources. This is much more efficient than trying to remove each of their resources one by one after they’re played.

This brings us to a key point: the game is blind to resources which never get used. The game can only see resources you actually use. By use, I mean cards you play, mana you spend, attacks you make, and so on. Resources which you could have used but didn’t don’t exist as far as the game is concerned. If you lose the game with a full hand of cards, it’s like those 10 cards never existed in the first place. If you imagine a player who didn’t get to draw cards for 5 turns of the game losing, that’s not terribly surprising, yet that’s effectively what happens when a player loses the game with 5 cards sitting in their hand they never played.

When you see players lose and get frustrated after dutifully cleaning up the board and collecting cards in their hand, you should now understand what went wrong: they forgot (or weren’t able) to convert their limited resources into plays that the game can see; into plays that win the game.

The name of the game is not “have a lot of resources,” as much as it’s, “use resources to kill the opponent.”

This line of thought can be extended to every resource in the game. If you have six mana you could have spent during a turn but only used 4, it’s as if that extra two mana didn’t exist. Imagine how much your game plan would typically be hurt if you couldn’t spend two mana on one of your turns. If you have 30 cards in your deck but only saw 10 of them during the game, then it’s as if those other 20 didn’t exist. If the minions you play are weaker than your opponents, it’s like you’re just giving up stat points or other beneficial effects you could have had.

Hearthstone is a game of utilized resources; not a game of potential resources. If you are not using your resources effectively, you are giving your opponent an opportunity to beat you on the grounds that they simply have more stuff: more mana, more cards, more stats, more anything.

This is counterintuitive to some players on a visual level, as they might see themselves holding a full hand of cards and thinking they have more resources than their opponent who is only holding two cards. However, if that state of affairs is the result of the opponent actually playing their cards and the game ending in a loss for you before you play yours, then you didn’t meaningfully have more resources than them. A similar issue can arise with respect to board control. It’s not uncommon for players to see that they’re ahead on board because they’ve been trading down opposing minions all game. However, all that time spent trading was time they didn’t attack the opponent’s life total, which can give the opponent more time to draw cards and spend mana which ultimately result in a win through burst damage or some other large threat.

With that in mind, let’s talk a bit about how to best use your resources.

Rule 1: Play your cards so they’re in play

Cards which you do not put into play fundamentally do not exist in that game. As the ability to play cards determines how many resources you actually have, you want to have a deck that is consistently able to play its cards and then actually play them when you can.

An important question you want to think about when you’re looking at your deck or hand is, “how often will the cards I have actually be playable?” If your deck contained nothing but 1-cost cards, you could begin playing cards on turn one 100% of the time and continue playing more of them each turn until your opponent was dead or you ran out of things to play. By contrast, if your deck contains nothing but 6-cost cards, you can begin playing cards on turn 6, and only play 1 card per turn.

In that simplified example, it’s clear which deck will have trouble using the cards it draws and which deck will not. Even if the 6-cost cards are all more independently powerful than 1-cost cards, they’re functionally useless if you cannot consistently get them out of your hand and into play.

For this reason, most powerful and successful decks in Hearthstone tend to play far more cheap cards than expensive ones. As an example, I’ve included screenshots below of some popular decks that players were seeing in Standard when I wrote this. Outlined in green are the cards in the deck that cost 5 or less mana, while outlined in red are the cards that cost 6 or more. You will see a clear pattern. Decks are composed almost exclusively of cheap cards. In fact, several of the more expensive cards in red can be discounted and aren’t always played for the mana cost on the card.

Now maybe you’re thinking to yourself, “Those decks are focused on the early game and that’s why they play cheap cards.” In that case, we can look at later-game archetypes.

Here, much the same picture emerges. We only see an appreciable-number of expensive cards in Control Warlock and Primordial Druid. In Druid, the intent is to play Overgrowth, which allows you more mana to play things earlier (making expensive cards more affordable by reducing the time they’re dead in hand), and Warlock, which plays the expensive cards largely in the service of being able to corrupt Tickatus and Strongman (both require you play things that cost more mana while they’re in your hand to be good).

Finally, we could even look at Wild decks to ensure the point is driven home:

You’ll notice here some cards are outlined in orange. These cards are included in the decks specifically because their mana cost gets discounted by the things the deck naturally does and are frequently intended to be played for 0 mana. Even the later-game focused Highlander Priest only plays 3 cards that cost more than 5 mana.

To reiterate, the reasons successful decks tend to play lots of cheap cards are because cards that don’t get played don’t effectively exist and cheap cards are easier to get into play. You can play them on earlier turns or squeeze them into later turns more effectively.

If you want to improve at Hearthstone, one of the major steps you need to take is to ensure the cards in your deck are going to be consistently playable. If their cost is too steep they won’t consistently have any impact, no matter how large or cool their effect might seem. Large- and cool-sounding effects are functionally insignificant and boring when you can’t actually play them consistently.

Now that we have seen why we want to ensure our cards are playable in theory, we want to move onto putting them into play in practice. A major issue many players struggle with is their Inability to play cards which are playable. They have a card which they could put into play, but then they simply don’t play it. This is typically because the cards have some effect - some bit of additional text - which makes them better if you play them under specific conditions. We can look at one such example: Shadowjeweler Hanar

Hanar is a 2-mana 1/4 minion that discovers a secret after you play a secret, so on turn 2 this card can be put into play as a 1/4. This line of play allows you to spend your mana and put a minion into play. That minion can then attack on future turns - dealing damage to the opponent or their minions. If it survives, you then no longer need to spend 2 mana getting it into play that next turn to utilize his ability and can spend that 2 mana playing secrets, or other minions, or spells, instead. Because you don’t always have 2 mana to spend on Hanar, putting him into play when you have that mana seems desirable.

It’s fairly common for many players to never consider this line of play because they get too fixated on the text of Hanar. They start thinking about the fact that putting Hanar in play leaves him vulnerable to removal, and if Hanar gets removed before giving you one or more secrets, you’re missing out on a possible resource. In fact, the longer you wait to play Hanar, the more possible resources he can generate. This causes players to hold the card on turn 2, because they’re too afraid of removal and losing valuable resources later...

...And then they also hold him on turn 3. After all, Rogue secrets cost 2 mana, so if you play him on turn 3 you risk losing that value as well. So maybe you should play him on turn 4 with a secret to ensure you get that value...but what if you don’t even have a secret in hand, or waited even longer? Then you could play another secret off him for sure...but then maybe he would be even better on turn 7 when you could get more secrets…

Eventually, the result of all that waiting is Hanar begins to rot in the hand and have no impact game after game. Players become too afraid of what they might lose out on in the future that they lose sight of the fact that the future payoff they’re saving for might not exist. They save the card for a big payoff, but the game begins to demand their limited resources do other things, and they just never have the time to reach the dream scenario of making huge numbers of extra secrets.

You’ll notice here some cards are outlined in orange. These cards are included in the decks specifically because their mana cost gets discounted by the things the deck naturally does and are frequently intended to be played for 0 mana. Even the later-game focused Highlander Priest only plays 3 cards that cost more than 5 mana.

To reinforce this idea that you want powerful cards and not necessarily cheap ones in the early game, we could also look at some current Control Warlock data. The most expensive card in Demonhunter, by quite a margin, is Skull of Gul’dan. Despite it costing six, it’s the best keep in the mulligan and it’s not close. The same can be said of Soulciologist Malicia in Warlock. It tends to be the best card by a wide margin, yet is one of the more expensive cards in the deck. Interestingly, despite both cards being expensive and the best card by a wide margin, Warlocks seem to be keeping Malicia far less than Demonhunters are keeping Skull. This appears to be a mistake of Warlock players.

These binary decisions - do I keep this card or mulligan it - might seem simple as the answer is either a “yes” or “no”, but they can require the use of copious amounts of both data and skill to get right. Understanding that mulligans are about power, not mana cost, can lead to major gains in win rate.

... [Content truncated for brevity in this format] ...

Lesson 4: Interaction And The Clock

4.1: TheNature of Interaction

On a basic level, interaction involves things having an effect on each other. Two things - we can call them X and Y - interact when the behavior of X changes the behavior of Y and vice versa. X would do one thing on its own, but does something different when it encounters Y. In Hearthstone, this typically takes two different forms:

• Explicit Interaction: This is when one card directly targets or has an effect on one or more other cards. Minions attacking into minions is one example, as would a spell targeting a minion. When cards “touch” you have explicit interaction, and many players focus a lot on this type when they think about what interaction in Hearthstone means.
• Implicit Interaction: This when the actions of one player change the actions of the other. One player would have taken action(s) X, but because their opponent did something, that player now takes action(s) Y. This type of interaction often goes unappreciated, despite being the most common type of interaction in the game, as it’s harder to visually see.

The goal of a game of Hearthstone is to reduce your opponent’s life total to 0. Because of that fact, when you’re playing Hearthstone you should not ever desire interaction, so long as your goal is to win. There are no wins awarded for interacting the most, whether that means destroying all opposing minions or playing around things consistently. You should become totally comfortable with the idea of jamming damage into your opponent’s face until they force you to do something else.

As the old saying goes: bad players go face, good players learn to trade, and great players learn to go face again. When it comes to interaction, your job is to figure out whether your opponent is forcing you to interact. If they aren’t, your goal should be to execute your own game plan as powerfully as possible. Force the opponent to interact with you and don’t interact when it’s not necessary.

... [More content continues with examples including Bloodfen Raptor, Brawl, Hanar, mulligan strategies, and Clock concepts]

4.2: The Clock

There’s a concept I’d like to refer to as "The Clock". What we are referring to are the time pressures a deck places on the opponent, or you can think about it as, "when does a deck typically win a game?" Some decks might have a fast clock, where they attempt to apply pressure to end a game quickly, perhaps turn 5, forcing the opponent to stop them during that window of time or lose. Other decks have slower clocks, intending to win a game by turn 10 or beyond, forcing an opponent to get under them before that point or lose. Some decks have multiple plans they can alternate between, where they can present faster or slower clocks depending on how they play things out.

... [More content continues with detailed advice on clocks, matchups, and strategic framing]

Lesson 5: Deck Building and the Importance of Data

So far we’ve been talking about attitudes and general principles of the game. This has been our initial focus because they are completely under your control and impact every game of Hearthstone you will play in very meaningful ways.

As such, the next topic we should discuss is deck building, because this is both something that can affect every game of Hearthstone you play and is entirely within your control. Improving your deck building will have important downstream consequences on your performance in every game. If you build a deck poorly, you are on track to lose games before they even begin.

I’m going to start off with what some might consider a harsh truth: if you want to win, the vast majority of players are better off ignoring the deck-building stage and copying successful lists from reputable sources (such as Vicious Syndicate). There is also no difference between “meta” decks and “off meta” or “homebrew” decks. “Meta” decks are the extremely-small subset of decks people made that actually worked. Every deck - popular or not, powerful or not - started off as someone’s original idea.

... [Data-driven discussion of data quality, HSReplay, HSGuru, and the value of expert analysis, with emphasis on sample size, source bias, and the proper interpretation of win rates]

4.2: Tips for Deck Builders

While data is exceptionally useful in figuring out what worked, it does have one shortcoming: it can only tell you about things that have happened. If there are ideas out there which are unexplored, the data will not have anything useful to tell you.

• Tip 1: Advance your own game plan first
• Tip 2: Synergy wins games
• Tip 3: Not all explicit synergy belongs in your deck
• Tip 4: Cards have hidden text
• Tip 5: There’s no such thing as an uncuttable card
• Tip 6: Don’t focus on the flashy.
• Tip 7: Avoid tech cards
• Tip 8: Avoid building or tinkering reactively

Lesson 6: The Mulligan Phase

Once you have your deck built and understand its overarching goals, the next most important thing you can do is improve your mulligan decisions. The reason here is simple: you will mulligan every single game. If you can improve here, you will be improving every single game you play, so the relative gains in performance for the time you put in are huge. The difference between having your best and worst cards as soon as possible can be the difference between a win and loss.

6.1: Don’t get baited by mana cost or synergy

... [Mulligan data, data interpretation cautions, and examples such as Miracle Rogue mulligan decisions]

6.2: Don’t get baited by the name of a deck

... [Discussion of deck naming confusion, Tickatus Warlock as an example]

6.3: Going First vs Second

... [Analysis of mulligan changes when going first vs going second, coin effects, and strategic implications]

Lesson 7: The Skill Cap

Not all decks in Hearthstone are created exactly equal with respect to their power. Some decks are just better than others, and that fact is well understood. What is less well agreed upon is how much one deck or another can improve with experience. Some decks are more complex than others. They present their pilots with more possible choices and plays. When this is the case, it can create an interaction between the skill of the pilot and the power of the deck. While better players tend to win more than worse players, better players might also be able to improve the performance of one deck more than they can improve the performance of another.

... [Concepts: skill cap, win rate components, data biases, sample size, source bias, and agency eliminators]

7.1: The many components of a win rate

Three primary components: (1) The deck’s power, (2) The pilot’s skill, (3) Random factors. Each contains sub-components. This section breaks down the core ideas and illustrates how skill, luck, and meta interplay affect observed win rates.

... [Further subsections 7.2, 7.3, 7.4, 7.5 with extensive discussion on player luck, data interpretation, and agency eliminators]

Lesson 8: Tilt

Tilt is a performance killer. When you’re frustrated, your decision-making deteriorates and you justify losses instead of learning. The guide offers practical strategies to counter tilt: taking breaks, changing focus (e.g., streaming or talking through moves out loud), recognizing that you’re playing against real people with their own goals, and accepting that not every game will end in a win.

Concluding Thoughts

Hearthstone is a very hard game to master, and building towards this mastery can seem daunting. However, this building, learning, and improving is what makes games so compelling. Without the urge to improve, all that Hearthstone offers you are colorful things to click on, and many games could scratch that itch just as well, if not better. To truly appreciate and explore the depth this game has to offer, you need to be willing to adopt a learning mindset and be willing to understand and accept reality for what it is, rather than defend your own perception of it. It can be a humbling experience, accepting just how many times you make mistakes.

... [Final reflective notes about the author’s experiences with data, statistics, and personal growth]

Understanding and Interpreting Hearthstone Statistics

Interpreting statistics - especially Hearthstone statistics - can feel easy. It isn’t. This guide will help you understand how to understand what you’re seeing on websites like HSReplay or HSGuru. Currently, HSReplay is useless without a premium membership, while HSGuru is free and has more data.

I. WHAT DATA IS USELESS

When it comes to HSReplay, that site will show you a lot of information that should be ignored. This section is mostly about that site. One main thing to be worried about is the “Meta” tab found on the top of the HSReplay site’s banner, which can be seen in the picture below. That tab - in theory - is supposed to give players a view of what decks are winning at different ranks. So, if you wanted to see what the overall state of the game was for, say, legend ranks, you just sort by “Legend,” and we can see that the best performing decks are (at time of writing), Highlander Hunter, Tempo Demon Hunter, Dragon Hunter, and Bomb Warrior in Tier 1. In Tier 2 we see that Pirate Warrior, Murloc Paladin, Egg Warrior, and Malygos OTK Rogue are the next 4 best decks, and so should immediately be able to tell that something has gone wrong…

... [Phenomena around data bias, misclassification, and observed vs weighted win rates]

II. WHAT DATA IS (MORE) USEFUL

Returning to the top of the site, we can now visit the “Decks” tab. This is where we see the performance of specific deck lists, rather than archetypes as a whole. You can also see this on HSGuru when you are using the “decks” tab.

... [Details about how to select decks, sample size, and the dangers of relying solely on win rate without considering sample size and source bias]

III. WHAT DATA IS (THE MOST) USEFUL

To really get useful data out of HSReplay and HSGuru, then, we’re going to have to enter the specific deck lists themselves. Within a deck, player skill will be controlled for, and HSReplay will be working with full information. This allows us to get stats on each card within the deck and where most of the useful information on the site comes from. So, let’s fire up the most popular Tempo Demon Hunter list in Legend since the most recent patch…

... [Discussion of time frames, data corruption due to patch timing, and the need to use weighted vs observed win rates]

IV. PRACTICAL TAKEAWAYS

• Always consider sample size when evaluating win rates.
• Distinguish observed win rate from weighted win rate.
• Be wary of deck names and class-level biases in meta data.
• Use both HSReplay and HSGuru with understanding of their data collection methods.

These are the core ideas from the documented material, preserved here to remain faithful to the source while enabling practical use in Hearthstone decision-making and learning.

Notes on Data Handling and Visualization

The document includes numerous screenshots and charts illustrating mulligan decisions, card stats, and deck performance. Specific examples include comparisons of different deck lists that differ by a single card (e.g., Deafen vs Aman’Thul), the impact of the coin on mulligan decisions, and per-card drawn WR vs Mulligan WR. The charts emphasize how small sample sizes and source biases can distort perceived deck strength, and how drawing order and mana costs can influence card value in different game states.

Final Takeaways

• A learning mindset is essential to improve at Hearthstone; accepting mistakes and using data to refine strategies leads to more consistent enjoyment and longer-term success.
• Data sources (HSReplay, HSGuru, Vicious Syndicate, etc.) provide powerful insights but require careful interpretation to avoid biased or misleading conclusions.
• The Mulligan, resource management, and clock concepts are central to building and playing effective decks.
• The skill cap concept highlights how player experience can lift certain decks more than others, but this is relative and context-dependent.

If you want to dive deeper into the data, you can explore the recommended sites (HSReplay, HSGuru, Vicious Syndicate) and the specific deck lists discussed in the document to practice data interpretation and deck refinement. The goal is not to rigidly follow a single path, but to continuously learn and adapt using data-driven methods.