Out with the old, in with the new. Hearthstone has officially done away with rarity-based drafting, and has gone on to a power level-based one. I had some questions in my previous look at the draft, but it is great to finally dive in myself, to see what it looks like.

Methodology

I drafted a Paladin Arena in Arena 10.4. I took a screencap of every pick.

I went to hsreplay.net to find stats for Paladin Arenas. Stats are for the last 14 days, delayed half an hour, of this writing.

I copied the “Deck winrate” and “Played winrate” for each card.

I used Google Sheets to calculate the standard deviation for each pick. This was done for “Deck winrate” and “Played winrate.”

Picks

Deck winrate table

The cards were labeled A, B, C, from left to right.

SDdwr represents the standard deviation between the 2 or 3 picks.

A new Arena card, Hand of Salvation, was excluded from the data, in picks 27 and 28.

Pick Adwr Bdwr Cdwr SDdwr 1 55.60% 58.20% 57.10% 1.31% 2 58.30% 58.40% 56.40% 1.13% 3 61.90% 60.50% 62.20% 0.91% 4 57.70% 59.20% 57.10% 1.08% 5 60.20% 60.30% 60.50% 0.15% 6 60.70% 61.60% 61.80% 0.59% 7 60.80% 61.80% 61.90% 0.61% 8 59.40% 59.60% 60.10% 0.36% 9 60.20% 59.60% 60.70% 0.55% 10 61.60% 60.70% 62.20% 0.75% 11 45.90% 57.60% 58.80% 7.13% 12 60.50% 58.50% 58.60% 1.13% 13 58.60% 60.00% 59.50% 0.71% 14 58.90% 59.10% 59.20% 0.15% 15 60.80% 60.20% 60.30% 0.32% 16 57.00% 46.80% 56.60% 5.78% 17 57.70% 58.80% 55.50% 1.68% 18 59.30% 58.40% 60.00% 0.80% 19 59.60% 58.90% 61.10% 1.12% 20 58.10% 65.30% 56.70% 4.61% 21 59.40% 60.10% 59.90% 0.36% 22 50.80% 46.80% 54.60% 3.90% 23 61.90% 61.60% 60.80% 0.57% 24 60.90% 61.00% 60.70% 0.15% 25 60.70% 59.90% 60.70% 0.46% 26 59.30% 59.80% 58.60% 0.60% 27 . 59.60% 57.40% 1.56% 28 57.40% . 59.30% 1.34% 29 59.70% 60.70% 58.60% 1.05% 30 60.60% 60.10% 62.20% 1.10%

Played winrate table

The cards were labeled A, B, C, from left to right.

SDdwr represents the standard deviation between the 2 or 3 picks.

A new Arena card, Hand of Salvation, was excluded from the data, in picks 27 and 28.

Pick Apwr Bpwr Cpwr SDpwr 1 46.70% 48.40% 43.80% 2.33% 2 51.00% 46.50% 48.60% 2.25% 3 65.10% 56.70% 61.00% 4.20% 4 46.10% 46.50% 46.40% 0.21% 5 52.70% 54.70% 51.40% 1.66% 6 56.60% 57.10% 55.70% 0.71% 7 59.60% 55.70% 65.10% 4.72% 8 48.20% 50.90% 51.90% 1.91% 9 57.70% 50.90% 53.00% 3.48% 10 57.10% 56.60% 61.00% 2.41% 11 27.40% 47.30% 49.60% 12.21% 12 54.80% 51.60% 49.00% 2.91% 13 50.20% 53.20% 50.50% 1.65% 14 50.60% 49.10% 55.60% 3.40% 15 53.10% 53.40% 54.90% 0.96% 16 45.00% 28.50% 41.40% 8.68% 17 46.10% 50.70% 45.50% 2.84% 18 49.20% 47.40% 52.80% 2.75% 19 51.30% 54.60% 52.70% 1.66% 20 51.60% 43.70% 54.40% 5.55% 21 48.20% 51.90% 55.20% 3.50% 22 33.90% 28.50% 47.80% 9.96% 23 65.10% 57.10% 59.60% 4.09% 24 54.40% 55.70% 56.60% 1.11% 25 59.20% 54.30% 54.30% 2.83% 26 50.50% 50.90% 49.00% 1.00% 27 . 47.10% 43.60% 2.47% 28 43.60% . 49.20% 3.96% 29 50.90% 53.00% 49.00% 2.00% 30 57.90% 53.00% 53.70% 2.65%

Limitations

This is just one draft, so small sample size. But it does provide 30 data points!

I drafted Paladin, a class with pretty good winrates. I suspect a bad Arena class would give more discrimination in winrates between cards.

The data was pooled from the last 14 days, which includes all of Wildfest. It is unclear if static Wildfest data was used to group cards, or if it will be a dynamic system with the winrates.

Standard deviation isn’t the best measure for 2 or 3 picks, but I was too lazy to figure out the best test.

Results

The standard deviation of deck winrate was very low, with most values falling within 0-2%. Pick 11 (Street Trickster / Ebon Dragonsmith / Midnight Drake) had the highest deviation, and Pick 16 (Frostwolf Grunt / Eye for an Eye / Lesser Pearl Spellstone) second. These were the only standard deviations above 5%.

The standard deviation of played winrate was higher. Pick 11 had the highest rate again, and Pick 22 (Small-Time Recruits / Eye for an Eye / Sabretooth Stalker) had the second. Along with Pick 16, these were the three abnormally higher rates.

Discussion

The power levels seemed to be grouped by deck winrate. While Hsreplay data is not perfect, it takes a sample from actual data. Overall, the deck winrates were fairly consistent among 3 picks.

There appears to be a distinction from premium cards from good cards. Cards like Vinecleaver, Spikeridged Steed, and Rallying Blade were grouped together often.

The premium pool was rather small for this draft. I drafted 2 Vinecleavers, 1 Rallying Bad, and 1 Spikeridged Steed. This could give Arena a more constructed feel, and definitely making playing around cards more important.

There were 2 legendary picks in this draft. I definitely saw a premium legendary group, and an average-ish legendary group.

The bad cards have greater variance in winrates. As shown in Pick 11, it appeared Street Trickster didn’t really belong with the other two picks. Possibly, there isn’t a really bad pool, and the really bad cards are grouped with just bad cards.

More data is needed. We don’t know how many card pools there are from this one draft, or what are acceptable differences in card winrates to be in the same pool. Obviously, more cards in other classes helps as well. Do your own analysis!