Friday, March 2, 2018

Tespa Hearthstone Collegiate Championship Meta Report: Week 1

As an analytically minded person, I'm very aware of the success one can find in using analytics to make decisions and how it translates to real-world success. I've written mostly about the impact analytics can play in baseball, but analytics has its place in Hearthstone as well - an esport that is near and dear to my heart. As a participant in the 2017 Tespa Hearthstone Collegiate Championship tournament, I realized that I could use data to my advantage and to others' advantage, and so I've prepared this meta report on the Tespa meta to explore how the tournament is shaping up.

Tournament Format

For those of you unfamiliar with the format of the Tespa tournament, I will briefly explain - teams from schools across the country compete in a Swiss-style round-robin tournament format for the regular season of the tournament. In order to qualify for the next stage of the tournament, teams must go at least 5-2 in regular season play. Once a team reaches 3+ losses, they are not assigned any further matches and are considered eliminated from the tournament.

Matches are played online against opponents via the Hearthstone Friend system. Teams bring four standard decks, one from a different class, and their opponents ban one deck after viewing their opponent's decklist simultaneously. Teams then queue up with one of their remaining decks and play a best-of-5 match. Once a team wins with a deck, that deck is banned from the rest of the match - hence, a team must win at least one game with each unbanned deck in order to win the match.

Deck Data

From scraping the deck data, it was quite obvious which classes were most popular - by a considerable margin. Of 773 teams for whom deck data was available, 366 brought exactly Priest, Mage, Warlock, and Paladin - 47% of all teams. Chances are if you didn't bring that exact lineup in week 1, your opponents did. This is very much in line with the current ranked meta in Standard - per, 6 of the top 7 archetypes on ladder belong to those four classes, and according to, Priest, Mage, Warlock, and Paladin are the top four most played ladder decks (or they were before the ranked ladder went down for maintenance).

Classes of Decks Brought, Week 1

136, Druid192, Hunter599, Mage626, Paladin649, Priest116, Rogue34, Shaman716, Warlock24, Warrior

Almost every team brought some form of a Warlock deck - 93% of all teams! The second most-brought class was Paladin at 81%. As could be inferred from above, not many teams brought Warrior or Shaman decks, though teams certain did attempt to spice things up in their fourth deck slot - Rogue, Hunter, and Druid saw a good amount of appearances in decklists for week one.

% of Teams Bringing a Class, Week 1


There also very little diversity with regards to archetypes. The dominant archetypes of the dominant classes were out in full force, with complementing variants. The most popular archetypes were Secret Mage, Murloc Paladin, Cube Warlock, Spiteful Priest, Control Warlock, Dragon Priest, and Aggro Paladin. These archetypes comprise, again, of 6 of the top 7 archetypes according to, so it's unsurprising to see them represented in such force.

In terms of bring rates, Secret Mage was brought by 54.2% of all teams, Murloc Paladin was brought by 53.6% of all teams, Cube Warlock was brought by 52.9% of all teams, Spiteful Priest was brought by 41% of all teams, and then no other archetype was brought by more than 29% of all teams. Of note at the bottom of the list, to say that some teams brought unique and unusual decks would be an understatement - I recorded at least one Recruit Hunter, one Quest Druid, and one Buff-Paladin. One enterprising team brought a lineup consisting solely of C'Thun decks!

Archetypes of Decks Brought, Week 1

Aggro Paladin, 166Aggro Token Druid, 6Big Druid, 2Big Priest, 95Buff Paladin, 1Burn Mage, 90C'Thun Druid, 3Control Mage, 1Control Paladin, 9Control Shaman, 1Control Warlock, 220Cube Warlock, 409Dragon Priest, 213Elemental Mage, 3Evolve Shaman, 18Exodia Mage, 29Jade Druid, 97Midrange Hunter, 33Mill Rogue, 59Miracle Rogue, 2Murloc Paladin, 414Pirate Warrior, 2Quest Druid, 1Recruit Hunter, 1Recruit Warrior, 1Secret Mage, 419Spell Hunter, 130Spiteful Priest, 317Tempo Rogue, 39Token Druid, 12Unknown Druid, 15Unknown Hunter, 28Unknown Mage, 57Unknown Paladin, 36Unknown Priest, 24Unknown Rogue, 16Unknown Shaman, 15Unknown Warlock, 30Unknown Warrior, 21Zoo Warlock, 57

Game Queuing Data

This year's Tespa Collegiate tournament is unique from previous years in that teams can now view opponents deck-lists before banning a deck, whereas previously, teams had only been able to view an opponent's class before banning a deck. We can contextualize this impact by looking at class ban rates versus archetype ban rates.

Note that our ban-rate data only includes winning classes. Tespa does not make specific ban-rate data publicly available, but we can infer the banned class of a winning team based on what three decks were used to win. However, given the nature of the conquest format, it is possible that the losing team might queue up with only two of their unbanned decks, or even one - hence, that data is absent. Thus, the ban-rate data may be skewed in that the teams represented in the ban rate data won their respective matches, and having a favorable class ban may have contributed to that. Still, the ban data is revealing regardless.

Below is the ban data for 318 Tespa matches, or 318 individual teams. Note that I recorded 410 games that took place last week, 92 of the matches either resulted in forfeits, failed to submit their decklists, or submitted corrupted decklists.

Warlock was the overwhelming favorite to be banned. Despite being as comparably popular as classes like Priest, Mage, and Paladin, Warlock was banned nearly three times as frequently as the next-most-frequently banned class, Paladin. By itself, Warlock accounted for 49% of all bans. While partly a result of teams bringing Warlock most frequently, the high ban-rate for Warlock is indicative of teams' fear of Cube Warlock.

Banned Classes, Week 1

Warlock, 156Rogue, 5Priest, 44Paladin, 61Mage, 40Hunter, 3Druid, 8

But looking at the archetype ban data, it becomes apparent that teams were either not aware that they could look at decklists prior to matches, or were not aware of the matchups surrounding them. Below shows how frequently a Warlock archetype was banned when it was brought by a team. You'll notice that the ban-rates for Cube Warlock are very similar to that of its other archetypes.

Warlock Archetypes Ban%, Week 1

0.177Control Warlock0.242Cube Warlock0.2Unknown Warlock0.211Zoo Warlock
However, Control Warlock matches up rather poorly against the three most popular decks from other classes - Spiteful Priest, Murloc Paladin, Secret Mage.

Spiteful PriestMurloc PaladinSecret Mage
Cube Warlock47%51%41%
Control Warlock35%59%39%
Zoo Warlock52%49%45%

While Control Warlock suffers poorly in the Murloc Paladin matchup, its ladder WR% suggest that it can be more easily farmed for wins by Spiteful Priest and Secret Mage, thanks to the nature of the Conquest format. Hence, it is more beneficial for teams running those archetypes (of which there are many in this tournament) to avoid banning Control Warlock, since it looks like a weaker archetype than Cube Warlock. In this sense, this indicates that many players were either ignorant of their ability to look up their opponents deck-list prior to the match, or ignorant of the matchup between Control Warlock and the meta-decks of the tournament.

Note, however, that we are using ladder win rates to compare matchups, which might not be representative of the tournament meta. We will return to this subject later in this article.

As discussed before, it looks beneficial for teams running the most popular decks to avoid banning Control Warlock. But note that Murloc Paladin, the most popular deck in the tournament, suffers heavily against Control. Therefore, teams will want to avoid accidentally queuing into Control Warlock with Murloc Paladin. While the frequency of teams queuing up with decks in later games of the match may vary, we can look at what class teams most frequently used to queue up with first.

For the most popular archetypes, I looked at which archetypes I knew were available to teams (i.e. all decks that I knew were unbanned - hence we have a case of winners bias again), and found how frequently teams who brought that deck queued up first with it. Teams with Warlock available brought that class out first most frequently, 75% of the time for Cube Warlock, 63% of the time for Control Warlock, and 59% of the time for Zoo Warlock. Teams with Jade Druid led with that deck most frequently after that, queuing up first with it 41% of the time.

% Of Teams with a given unbanned archetype going 1st with it, Week 1

0.2Aggro Paladin0.63Control Warlock0.75Cube Warlock0.23Dragon Priest0.41Jade Druid0.36Murloc Paladin0.27Secret Mage0.28Spell Hunter0.23Spiteful Priest0.59Zoo Warlock
Thus, teams with decks that are susceptible to losing to a given Warlock archetype and have not banned their opponent's Warlock should consider avoiding queuing with that deck first to avoid the matchup. For example, Zoo Warlock has a slight advantage over Spiteful Priest, so teams running Spiteful Priest against Zoo Warlock should avoid queuing with Spiteful Priest first.

Class and Archetype Win Rates

Which are the most powerful decks in the current Tespa meta? To examine this question, I looked at all games of the tournament and compared each class and deck archetype's win rate to each other. First, the classes.

Paladin, not Warlock, surprisingly emerges on top. This makes sense, however - Paladin was not as frequently banned as Warlock, and Murloc Paladin is arguably a better archetype on ladder than any current Warlock archetype. Warlock has a sub-50% win rate, however - on the surface, this makes little sense for a class that was brought by 90%+ of all teams and banned in almost 50% matches. There may be multiple factors causing Warlock to have a sub-50% WR. For starters, the conquest format allows teams to simply avoid Warlock decks that they do not want to face so teams that may be unprepared to face Warlock can avoid doing so. And the decks that might face off against Warlock might see techs designed to target Warlock. In that sense, it's impressive that Warlock has a 49.7% WR in the face of all that.

Class Win Rates, Week 1

Perhaps Warlock's sub 50% win rate also comes from the saturation of archetypes weaker than the much-feared Cube Warlock. Cube and Zoo Warlock posted win rates of 51.3% and 51.2% respectively, but Control Warlock had a rougher go at it, posting a win rate of 48.2%.

Several surprising things pop out regarding the Archetype Win Rates. Aggro Paladin posted a win rate ~3% higher than Murloc Paladin, likely due to teams running hungry crabs in their deck. Spell Hunter, despite being brought by only 130 teams, posted a stellar 58% win rate. And Dragon Priest was one of the worst archetypes among the most popular decks, posting a 46% win rate.

Archetype Win Rates, Week 1

  0.4070.593Aggro Paladin0.5180.482Control Warlock0.4870.513Cube Warlock0.540.46Dragon Priest0.50.5Jade Druid0.4420.558Murloc Paladin0.4920.508Secret Mage0.4160.584Spell Hunter0.4730.527Spiteful Priest0.4880.512Zoo Warlock

In terms of matchups, it's not hard to see why Spell Hunter was so successful - its only weak matchups were against Jade Druid and Control Warlock. Consider, however, that the small sample size of decks involving Spell Hunter may allow random variance to affect the results of this survey, - Spell Hunter has a negative win-rate against most of the major archetypes except for Secret Mage according to's ladder results.

For/AgainstSpell HunterDragon PriestAggro PaladinJade DruidZoo WarlockMurloc PaladinCube WarlockControl WarlockSpiteful PriestSecret Mage
Spell Hunter50%50%50%33%50%56%83%33%56%70%
Dragon Priest50%50%25%20%33%44%47%50%15%59%
Aggro Paladin50%75%50%33%68%60%17%100%50%
Jade Druid67%80%67%50%100%58%20%100%33%65%
Zoo Warlock50%67%0%43%100%50%44%
Murloc Paladin44%56%32%42%57%50%47%62%69%56%
Cube Warlock17%53%40%80%0%53%50%40%56%38%
Control Warlock67%50%83%0%38%60%50%40%29%
Spiteful Priest44%85%0%67%50%31%44%60%50%59%
Secret Mage30%41%50%35%56%44%62%71%41%50%

Tech Card Success Rates

Given the prevalence of Warlock, Paladin, and Druid, it would seem to be in teams' benefits to run tech cards to counter each archetype. Specifically, most Warlock archetypes are countered by decks running Spellbreaker, most Paladin archetypes are countered by Hungry Crab, and most Druid archetypes are countered by Skulking Gheist. To see how tangible the impact of running these cards had on these matchups, I looked at the win rates of decks running these cards against these classes.

The impact of playing Hungry Crab and Geist is immediate against Paladin and Druid, but Spellbreaker does not appear to be as useful of a tech card against Warlock archetypes in the Tespa meta, with its win-rate just about equal to the win rate of decks playing Warlock otherwise. Spellbreaker still has its uses in the tournament, however, in countering other decks especially given the current silence meta on ladder - decks running Spellbreaker in the tournament had a .628 win rate overall.

CardAgainst DeckWin Rate
Hungry CrabPaladin0.625
Skulking GeistDruid0.583


I'll conclude my report with a brief explanation of how I scraped the data, and some considerations regarding the data.

My data is essentially in two sections: the decklists from week one (of particular note now that teams can see opponents decklists prior to the match!) and the Tespa HS Championships match results (scraped from the tournament site). I scraped both sources and classified each deck based on its class and archetype (I looked at whether or not core cards of an archetype were present in the deck based on the 24 most popular archetypes from - so if a deck contained "Carnivorous Cube", "Voidlord', and "Doomguard", I classified the deck as "Cube Warlock"). My scraper, along with my week 1 data (decklists, archetype classifications, etc.) is available on my github here

Unfortunately, there's a lot of incomplete data. Many teams failed to submit deck-lists for week 1 and thus forfeited. I also encountered one or two teams with corrupt deck-lists, or only three decklists submitted. In scraping match results, I counted games involving these teams as forfeits. There were also many forfeits reported on the match site itself by way of no-show. Analysis involving decks brought to the tournament may involve teams who were involved in a forfeit, but match data analysis does not take into account forfeits. In all, about 22.4% of matches scraped were forfeits.

There are sadly some limits to the data. I do not have access to play-by-play data as one might have from, so I can't perform really advanced calculations with regards to win rate when drawing a particular card - fortunately, a game of Hearthstone in the tournament will play out roughly the same as a ladder game of Hearthstone at a high ranking. If you're interested in the particulars of that data, HSReplay has it readily available and I highly recommend their site (and especially their python package!). Fortunately, the data that I can find is extremely useful and fairly unique to the tournament. Hopefully, you learn something that gives you an edge (though not against my team!).

One Brief Note

If you've made it this far, I just wanted to say thanks for reading - this report was a lot of time and effort. If you're impressed with this, feel free to check out the rest of my site for baseball analytics. I'm a freelance/partially employed baseball writer/analyst with interest in doing analysis for esports and baseball. If you want me to write for your site, please contact me on twitter at! I'd love to write for you.

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