Patch 2.9 In-Depth Statistical Meta Report

Hey folks, Dr. LoR here with an updated in-depth stats-based meta report. Patch 2.9 wasn’t as major as many players were expecting, but even small changes can eventually percolate into some bigger meta shifts. Was that the case this time around? Here’s how the state of meta looked in the week that followed the latest patch.

• The 480k matches of data for the analysis below come from Mobalytics Meta Stats. The timeframe is June 2-8.
• I am relying on Mobalytics’s archetype algorithm, which uses champions and regions to define archetypes. This means that Shyvana Asol is separate from Shyvana Zoe Asol and Renekton Sejuani is different from Renekton Sivir Sejuani. Where appropriate, I manually combined Mobalytics archetypes that show slightly different champion combinations. This mainly concerned Dragons, Overwhelm, Ashe Noxus, Shurima Nox Aggro, Turbo Thralls, and Matron Cithria archetypes.
• I use Bayesian smoothing toward a win rate of 51%. It is a technique that allows avoiding statistical flukes. If you want to learn more about the concept, check out this explainer.
• I use Herfindahl-Hirschman Index (HHI) to calculate meta diversity. The smaller HHI is – the more diverse is the meta. Read this if you would like to know more about the method.
• Often I include 95% confidence intervals when talking about win rate stats. In that case, I provide two percentage numbers, saying that we can be 95% sure that the ‘true’ win rate for the deck lands somewhere in-between.

Most Popular Archetypes

Here are the play rates for the 20 most popular decks, sorted by rank. Each of these decks has at least a 1% play rate in Plat+. All of these decks together account for around 2/3 of Gold+Platinum and 4/5 of Diamond+Masters meta.

• Azir Irelia’s play rate decreased after the patch but remains high. Azir Irelia and Thresh Nasus continue to dominate the meta, followed by a trio of Turbo Thralls, Ez Draven, and Dragons – each of those three has around 6% PR. Together, these five decks are 45.5% of the meta at Plat+.
• Turbo Thralls is arguably the biggest news story of Patch 2.9, quadrupling in play rate since my last report. It’s strong against Dragons (70%), TLC (65%), Thresh Nasus (60%), even against EZ Draven (50%), but incredibly weak to Azir Irelia (22%).
• Azir Irelia, Thresh Nasus, EZ Draven, TLC, Turbo Thralls all start to see higher play rates the higher we climb the ladder. They established themselves as top-tier meta decks in the eyes of the player base.
• Meta diversity has increased compared to the last patch, with an HHI of 557 in Plat+ (to learn what is HHI, see Sources and Methodology section above). Diversity is great in Gold (HHI = 365), decent at Platinum (454), but not good in Diamond (656) and Masters (681). All of these numbers are way better than pre-balance, so I guess that aspect of Patch 2.9 at least worked.

Most Successful Archetypes

Below, you can see the win rates for the 20 highest play rate decks, again grouped by rank. I also included 95% confidence intervals (see Sources and Methodology section), which you can see as thin vertical lines on top of each bar.

• Riot has previously noted that 15% play rate and/or 55% win rate at Plat+ is their threshold for balance adjustments. Azir Irelia continues to surpass both of those. The nerfs to Blossoming Blade and Inspiring Marshal made these cards significantly worse, but Irelia’s ‘bug fix’ buff seems to have partially made up for it. The rise of Turbo Thralls also gave it a new easy prey.
• Aggro decks have some truly ridiculous win rates at Gold. If you’re in that rank, you should climb fast if you choose Shurima Noxus, Azir Irelia, or Spiders. However, these decks become significantly weaker at Diamond and Masters.
• Win rate stats for Diamond and Masters are spread very similarly, but Platinum feels closer to Gold in that aggro and midrange decks perform much stronger there than in higher ranks.

Below is a spreadsheet of all the decks with more than 800 matches in Plat+, sorted by win rate. The table is split into super-columns by rank. Under each super-column, you’ll find a sample size (match), the play rate (PR), win rate (WR), and the win rate adjusted using the Bayesian smoothing technique (bWR).

In addition, the Plat+ data includes 95% confidence intervals for each win rate (which means that, for example, we can be 95% sure that Azir Irelia has a ‘true’ win rate between 55.1% to 55.9%. See also in Sources and Methodology).

Most Meta-Defining Archetypes

In the chart below I’ve plotted win rates versus play rates of 29 decks in Platinum+, to demonstrate which archetypes can be seen as the most impactful in the current meta. I took 20 archetypes we’ve talked about in the previous sections of this report and added 9 other decks that have less than 1% play rate and at least 49% win rate – just to showcase some alternative fringe meta options.

In the graph, you can see ‘a dot’ and a ‘vertical line’ for each archetype. The vertical lines represent the 95% confidence intervals for win rates.

• Turbo Thralls and Dragons are both popular decks that look underpowered on stats.
• Aggro decks continue to be underplayed despite showing some good win rates – it can be said particularly about Shurima Noxus, Pirates, Spiders, and Overwhelm.
• I’d like to thank Cithria Matron, Sun Disc, Fiora All-In, and Malphite players for donating LP to the rest of the ladder. Your willingness to give up win rate in exchange for fun is appreciated.

Conclusion

Despite its nerfs, Azir Irelia continues to dominate the ladder, but to a little lesser extent than before (at least in terms of play rate).

The buffs to Malphite weren’t enough to sharpen the rock’s win rate just yet, but the buff to Taliyah has boosted Turbo Thralls to a status of a popular Tier 2 deck. However, I’d say that its current play rate is still higher than its win rate can justify.

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