Legend of the Poroking Statistics (2015)

Poroking mode statistics - with 280k games analyzed from the NA server.
Note that win rate is calculated for non-mirror games only.
Click on the column headers to sort.

Champion	Popularity	Win Rate
Aatrox	0.94%	39.15%
Ahri	8.41%	47.79%
Akali	2.42%	38.33%
Alistar	10.53%	58.29%
Amumu	7.38%	55.26%
Anivia	5.68%	45.73%
Annie	7.92%	47.64%
Ashe	13.86%	49.70%
Azir	10.32%	42.58%
Bard	9.53%	34.41%
Blitzcrank	25.58%	48.29%
Brand	15.31%	53.69%
Braum	3.87%	49.17%
Caitlyn	12.00%	51.49%
Cassiopeia	2.17%	47.34%
Cho'Gath	7.80%	45.76%
Corki	2.43%	43.62%
Darius	11.36%	51.83%
Diana	2.69%	49.28%
Draven	2.82%	50.23%
Dr. Mundo	11.00%	56.51%
Ekko	9.88%	44.07%
Elise	0.68%	44.60%
Evelynn	0.41%	40.59%
Ezreal	28.83%	48.35%
Fiddlesticks	9.06%	53.60%
Fiora	2.52%	47.17%
Fizz	7.60%	46.56%
Galio	7.67%	62.83%
Gangplank	8.74%	53.31%
Garen	14.82%	56.18%
Gnar	13.58%	48.53%
Gragas	2.77%	42.36%
Graves	4.95%	51.52%
Hecarim	2.10%	45.36%
Heimerdinger	10.56%	60.36%
Illaoi	21.06%	55.87%
Irelia	1.80%	48.34%
Janna	4.25%	56.52%
Jarvan IV	5.64%	46.41%
Jax	4.46%	44.46%
Jayce	6.99%	47.30%
Jinx	20.65%	50.85%
Kalista	9.35%	44.30%
Karma	5.61%	50.71%
Karthus	12.49%	50.63%
Kassadin	2.85%	42.84%
Katarina	16.89%	49.22%
Kayle	2.71%	45.59%
Kennen	3.62%	42.16%
Kha'Zix	1.45%	37.37%
Kindred	6.58%	41.91%
Kog'Maw	9.07%	57.05%
LeBlanc	6.75%	37.91%
Lee Sin	7.05%	38.08%
Leona	6.82%	54.43%
Lissandra	2.34%	45.86%
Lucian	9.25%	48.62%
Lulu	5.45%	43.03%
Lux	35.75%	56.37%
Malphite	13.17%	48.32%
Malzahar	8.29%	55.21%
Maokai	3.55%	58.03%
Master Yi	8.98%	48.91%
Miss Fortune	37.12%	55.76%
Mordekaiser	1.68%	48.42%
Morgana	12.23%	51.17%
Nami	3.78%	49.23%
Nasus	3.29%	48.31%
Nautilus	7.34%	57.81%
Nidalee	14.90%	38.98%
Nocturne	0.45%	40.43%
Nunu	2.33%	40.25%
Olaf	3.96%	48.08%
Orianna	9.06%	43.90%
Pantheon	3.03%	45.96%
Poppy	34.57%	43.81%
Quinn	2.64%	43.84%
Rammus	3.40%	58.45%
Rek'Sai	0.59%	40.32%
Renekton	2.38%	48.00%
Rengar	2.99%	39.10%
Riven	6.06%	41.69%
Rumble	2.63%	43.29%
Ryze	2.93%	44.55%
Sejuani	5.07%	51.43%
Shaco	7.59%	45.83%
Shen	2.65%	52.08%
Shyvana	1.26%	43.65%
Singed	5.19%	54.27%
Sion	6.85%	62.60%
Sivir	5.32%	49.88%
Skarner	3.24%	51.31%
Sona	19.69%	61.00%
Soraka	10.09%	44.29%
Swain	3.75%	56.97%
Syndra	8.00%	41.85%
Tahm Kench	7.39%	47.10%
Talon	5.35%	55.41%
Taric	2.54%	63.78%
Teemo	20.85%	58.54%
Thresh	7.37%	42.64%
Tristana	10.85%	45.52%
Trundle	2.23%	60.21%
Tryndamere	2.09%	42.18%
Twisted Fate	9.91%	46.72%
Twitch	3.59%	46.88%
Udyr	0.81%	44.30%
Urgot	0.94%	47.44%
Varus	15.13%	53.00%
Vayne	9.09%	48.50%
Veigar	15.17%	48.04%
Vel'Koz	9.94%	53.13%
Vi	1.47%	47.36%
Viktor	4.48%	47.22%
Vladimir	5.95%	60.08%
Volibear	3.40%	52.53%
Warwick	1.44%	50.11%
Wukong	7.84%	54.20%
Xerath	7.08%	48.71%
Xin Zhao	2.36%	46.80%
Yasuo	20.86%	46.50%
Yorick	1.10%	54.86%
Zac	8.04%	44.31%
Zed	10.74%	43.13%
Ziggs	14.60%	58.31%
Zilean	5.52%	48.79%
Zyra	4.80%	57.66%

Some other intersting tidbits:

• Overall, blue side won about 54.5% of the time.
• Out of a sample of 12179 Katarina games on record, she had at least one pentakill in 563 of them - a pentakill rate of 4.6% per game for the Katarina player. This is followed by Master Yi at 3.3% and Darius at 1.4%. On Summoners' Rift, Katarina and Master Yi usually have around 1-1.5% pentakill per game.
• The mean and median game length are 21.4 and 20.6 minutes respectively. The longest game on my record is 78 minutes; the shortest is 7 minutes.

See last year's statistics here.

One For All Statistics (2015)

One for All statistics - with 170k games analyzed from the NA server.
Note that win rate is calculated for non-mirror games only.
Click on the column headers to sort.

Champion	Popularity	Win Rate
Kindred	12.71%	36.13%
Yasuo	10.24%	55.15%
Tahm Kench	7.49%	41.94%
Lux	6.87%	64.63%
Darius	6.48%	71.81%
Heimerdinger	6.44%	65.53%
Blitzcrank	6.17%	44.54%
Bard	4.79%	18.07%
Veigar	4.74%	53.93%
Lee Sin	4.61%	57.02%
Ezreal	4.29%	48.42%
Ekko	4.07%	63.12%
Zed	3.91%	39.68%
Shaco	3.75%	42.37%
Riven	3.35%	55.02%
Brand	3.35%	60.13%
Garen	3.22%	74.07%
Azir	3.11%	17.30%
Gangplank	3.08%	37.84%
Mordekaiser	3.02%	53.31%
Katarina	2.86%	53.29%
Vel'Koz	2.67%	49.55%
Gnar	2.27%	58.88%
Ziggs	2.22%	31.02%
Master Yi	2.22%	64.35%
Nidalee	2.16%	26.75%
Fizz	2.16%	51.41%
Malphite	2.14%	65.90%
Sona	2.06%	57.06%
Rengar	2.01%	42.39%
Kalista	1.95%	41.99%
Jinx	1.94%	47.66%
Soraka	1.88%	29.39%
LeBlanc	1.75%	34.85%
Annie	1.69%	57.77%
Fiora	1.60%	52.89%
Zilean	1.59%	22.09%
Thresh	1.56%	36.29%
Vayne	1.55%	44.68%
Morgana	1.51%	61.91%
Wukong	1.46%	80.87%
Syndra	1.29%	38.28%
Teemo	1.28%	56.21%
Ahri	1.27%	63.87%
Anivia	1.27%	46.27%
Kennen	1.21%	71.12%
Twisted Fate	1.21%	49.48%
Singed	1.21%	23.08%
Fiddlesticks	1.19%	28.60%
Yorick	1.17%	51.48%
Kassadin	1.16%	39.44%
Malzahar	1.11%	51.54%
Dr. Mundo	1.11%	74.86%
Sion	1.10%	72.91%
Jayce	1.09%	58.15%
Cho'Gath	1.05%	72.57%
Alistar	0.99%	32.25%
Zac	0.98%	44.34%
Varus	0.96%	61.14%
Karthus	0.89%	44.36%
Hecarim	0.88%	59.05%
Rammus	0.85%	54.84%
Ashe	0.84%	53.06%
Pantheon	0.83%	66.26%
Vi	0.83%	64.72%
Lulu	0.81%	37.51%
Diana	0.80%	67.66%
Vladimir	0.79%	50.53%
Jarvan IV	0.74%	70.57%
Talon	0.72%	59.41%
Viktor	0.71%	29.28%
Galio	0.71%	61.89%
Taric	0.68%	30.86%
Zyra	0.68%	47.43%
Draven	0.66%	36.08%
Tryndamere	0.66%	61.24%
Xerath	0.64%	34.92%
Xin Zhao	0.60%	73.96%
Amumu	0.59%	68.39%
Poppy	0.59%	57.52%
Leona	0.57%	56.28%
Nautilus	0.57%	51.88%
Orianna	0.57%	34.31%
Volibear	0.57%	75.47%
Urgot	0.56%	47.61%
Shen	0.55%	52.86%
Braum	0.52%	21.00%
Swain	0.52%	53.32%
Evelynn	0.51%	38.90%
Olaf	0.48%	66.67%
Caitlyn	0.48%	52.03%
Nunu	0.47%	38.19%
Jax	0.45%	65.22%
Karma	0.45%	48.49%
Gragas	0.44%	30.12%
Cassiopeia	0.43%	34.93%
Rumble	0.43%	33.47%
Twitch	0.41%	46.20%
Miss Fortune	0.41%	71.33%
Kog'Maw	0.41%	56.53%
Rek'Sai	0.40%	28.00%
Tristana	0.39%	39.88%
Akali	0.38%	41.44%
Maokai	0.37%	54.68%
Kha'Zix	0.37%	50.88%
Aatrox	0.35%	69.34%
Nocturne	0.34%	76.80%
Nasus	0.32%	67.96%
Lucian	0.30%	38.48%
Skarner	0.29%	52.32%
Renekton	0.29%	65.42%
Nami	0.28%	32.22%
Lissandra	0.28%	42.22%
Trundle	0.28%	68.74%
Kayle	0.27%	62.11%
Warwick	0.26%	46.35%
Janna	0.24%	21.60%
Elise	0.23%	28.79%
Shyvana	0.22%	65.41%
Ryze	0.21%	34.25%
Irelia	0.20%	60.84%
Udyr	0.19%	41.56%
Sejuani	0.17%	55.67%
Quinn	0.16%	54.28%
Sivir	0.12%	51.22%
Corki	0.11%	49.22%
Graves	0.10%	46.91%

Overall, blue side won about 52.6% of the time. However, based on the limited sample size I have available, it seems that mirror matchups (where all ten champions are the same) have varying degree of blue side advantage.

Champion	Blue Side Win Rate	# of Games Collected
Overall	52.64%	168,867
Kindred	50.89%	1,006
Yasuo	53.31%	649
Darius	49.51%	612
Tahm Kench	51.47%	375
Heimerdinger	53.19%	329
Lux	54.51%	266

Black Market Brawlers Statistics

280k Black Market Brawlers (BMB) games collected with win rate computed per champion (non-mirrors only). Additionally, since BMB is very similar to Blind Pick, I collected 100k Blind Pick games from the same patch with comparable players for comparison.

Note that BMB games are Blind Draft - 6 bans are given. This has definite impact on champion popularity (see: Yasuo).

1. Win Rate and Popularity (Click on the columns to sort)

Champion	BMB Popularity	Blind Popularity	Popularity Difference	BMB Win Rate	Blind Win Rate	Win Difference
Aatrox	7.60%	5.29%	2.31%	53.97%	51.58%	2.39%
Ahri	11.60%	11.34%	0.26%	53.36%	53.02%	0.34%
Akali	4.40%	5.06%	-0.66%	47.84%	50.45%	-2.61%
Alistar	5.80%	6.66%	-0.86%	49.25%	49.06%	0.19%
Amumu	4.50%	4.28%	0.22%	54.48%	54.32%	0.16%
Anivia	2.90%	2.80%	0.10%	52.71%	50.99%	1.72%
Annie	11.90%	11.95%	-0.05%	51.16%	51.66%	-0.51%
Ashe	17.50%	16.85%	0.65%	51.20%	49.52%	1.68%
Azir	5.60%	6.64%	-1.04%	45.41%	46.48%	-1.07%
Bard	11.90%	15.47%	-3.57%	42.79%	43.03%	-0.24%
Blitzcrank	15.10%	17.96%	-2.86%	53.30%	54.09%	-0.79%
Brand	5.60%	4.49%	1.11%	52.39%	52.91%	-0.52%
Braum	6.40%	5.39%	1.01%	51.85%	52.70%	-0.85%
Caitlyn	13.90%	11.33%	2.57%	50.77%	49.70%	1.07%
Cassiopeia	2.60%	2.35%	0.25%	45.34%	45.31%	0.03%
Cho'Gath	7.80%	6.58%	1.22%	50.84%	51.80%	-0.96%
Corki	3.20%	4.26%	-1.06%	49.68%	49.51%	0.17%
Darius	16.30%	18.39%	-2.09%	49.05%	49.21%	-0.16%
Diana	16.60%	17.62%	-1.02%	51.35%	52.05%	-0.70%
Dr. Mundo	2.80%	2.49%	0.31%	47.66%	48.38%	-0.72%
Draven	6.20%	7.72%	-1.52%	50.13%	51.94%	-1.82%
Ekko	11.60%	10.95%	0.65%	47.11%	48.44%	-1.32%
Elise	7.60%	9.57%	-1.97%	51.52%	52.17%	-0.64%
Evelynn	4.90%	5.57%	-0.67%	45.74%	43.22%	2.52%
Ezreal	13.30%	13.10%	0.20%	46.01%	47.25%	-1.23%
Fiddlesticks	3.50%	2.99%	0.51%	47.24%	45.47%	1.77%
Fiora	7.70%	5.80%	1.90%	53.27%	53.71%	-0.44%
Fizz	13.90%	16.72%	-2.82%	50.13%	50.34%	-0.20%
Galio	1.70%	1.36%	0.34%	52.20%	51.60%	0.60%
Garen	10.60%	9.37%	1.23%	51.32%	51.43%	-0.11%
Gnar	9.40%	9.01%	0.39%	47.38%	48.79%	-1.41%
Gragas	3.20%	3.83%	-0.63%	45.69%	47.76%	-2.07%
Graves	14.40%	14.38%	0.02%	50.20%	49.43%	0.78%
Hecarim	4.70%	4.36%	0.34%	49.17%	49.43%	-0.26%
Heimerdinger	9.70%	6.03%	3.67%	54.55%	54.76%	-0.21%
Irelia	5.90%	6.87%	-0.97%	49.78%	51.06%	-1.27%
Janna	7.30%	6.56%	0.74%	54.11%	53.95%	0.17%
Jarvan IV	5.50%	5.37%	0.13%	50.26%	49.77%	0.50%
Jax	10.50%	9.34%	1.16%	52.11%	51.19%	0.92%
Jayce	4.10%	4.46%	-0.36%	46.75%	48.75%	-2.00%
Jinx	22.40%	19.51%	2.89%	52.09%	51.39%	0.70%
Kalista	6.80%	7.93%	-1.13%	46.63%	46.24%	0.38%
Karma	5.10%	3.57%	1.53%	50.39%	48.91%	1.49%
Karthus	2.00%	1.80%	0.20%	50.43%	48.63%	1.79%
Kassadin	1.50%	1.62%	-0.12%	40.49%	42.55%	-2.06%
Katarina	9.20%	10.47%	-1.27%	50.15%	49.95%	0.20%
Kayle	7.20%	7.72%	-0.52%	52.15%	51.55%	0.59%
Kennen	2.50%	2.71%	-0.21%	48.66%	50.30%	-1.63%
Kha'Zix	6.00%	6.77%	-0.77%	46.12%	46.92%	-0.80%
Kog'Maw	7.70%	9.52%	-1.82%	48.09%	49.06%	-0.97%
LeBlanc	5.90%	5.78%	0.12%	44.61%	46.13%	-1.52%
Lee Sin	12.70%	19.03%	-6.33%	44.56%	46.01%	-1.45%
Leona	10.20%	8.45%	1.75%	54.09%	53.70%	0.39%
Lissandra	1.70%	1.68%	0.02%	50.46%	51.80%	-1.34%
Lucian	6.10%	7.27%	-1.17%	48.83%	47.56%	1.27%
Lulu	5.50%	4.71%	0.79%	49.91%	49.90%	0.01%
Lux	15.30%	12.65%	2.65%	51.43%	51.61%	-0.17%
Malphite	7.20%	8.87%	-1.67%	51.86%	53.31%	-1.45%
Malzahar	7.10%	3.10%	4.00%	55.76%	55.35%	0.41%
Maokai	3.70%	3.84%	-0.14%	48.76%	50.45%	-1.69%
Master Yi	16.60%	18.05%	-1.45%	51.79%	50.18%	1.61%
Miss Fortune	28.40%	21.37%	7.03%	51.37%	51.69%	-0.32%
Mordekaiser	2.90%	2.06%	0.84%	53.29%	50.59%	2.69%
Morgana	10.80%	9.27%	1.53%	50.38%	50.53%	-0.16%
Nami	8.60%	8.87%	-0.27%	50.58%	51.19%	-0.61%
Nasus	8.60%	8.97%	-0.37%	48.66%	50.37%	-1.71%
Nautilus	15.60%	16.76%	-1.16%	51.16%	51.21%	-0.05%
Nidalee	11.80%	14.26%	-2.46%	45.44%	45.72%	-0.28%
Nocturne	4.50%	4.41%	0.09%	52.48%	50.16%	2.32%
Nunu	5.50%	3.42%	2.08%	50.55%	47.47%	3.07%
Olaf	4.40%	3.98%	0.42%	48.41%	46.61%	1.80%
Orianna	4.40%	5.59%	-1.19%	48.20%	47.17%	1.03%
Pantheon	5.40%	5.04%	0.36%	48.05%	50.00%	-1.95%
Poppy	1.50%	1.72%	-0.22%	45.67%	46.63%	-0.97%
Quinn	11.30%	12.28%	-0.98%	47.50%	48.85%	-1.36%
Rammus	2.40%	1.92%	0.48%	51.85%	54.11%	-2.26%
Rek'Sai	4.50%	4.89%	-0.39%	46.97%	47.99%	-1.02%
Renekton	4.10%	3.84%	0.26%	52.52%	51.28%	1.25%
Rengar	10.50%	12.34%	-1.84%	46.25%	47.10%	-0.85%
Riven	10.40%	15.50%	-5.10%	48.57%	49.79%	-1.22%
Rumble	2.50%	3.44%	-0.94%	46.83%	50.73%	-3.90%
Ryze	2.00%	2.39%	-0.39%	40.22%	41.48%	-1.26%
Sejuani	2.70%	2.45%	0.25%	51.28%	50.54%	0.73%
Shaco	9.20%	8.40%	0.80%	47.04%	48.14%	-1.10%
Shen	7.10%	7.84%	-0.74%	50.43%	51.01%	-0.59%
Shyvana	12.00%	10.19%	1.81%	55.19%	52.86%	2.33%
Singed	3.20%	2.78%	0.42%	51.23%	48.58%	2.65%
Sion	4.70%	3.18%	1.52%	52.68%	52.52%	0.16%
Sivir	8.70%	9.57%	-0.87%	52.34%	52.03%	0.31%
Skarner	1.90%	1.32%	0.58%	50.76%	52.59%	-1.84%
Sona	13.90%	8.99%	4.91%	53.26%	54.21%	-0.95%
Soraka	6.80%	6.49%	0.31%	51.70%	50.27%	1.44%
Swain	2.80%	1.95%	0.85%	50.88%	52.68%	-1.80%
Syndra	2.00%	2.11%	-0.11%	48.18%	46.65%	1.53%
Tahm Kench	24.60%	24.13%	0.47%	42.25%	42.54%	-0.30%
Talon	4.80%	4.79%	0.01%	51.59%	51.42%	0.16%
Taric	2.40%	1.92%	0.48%	53.16%	50.56%	2.61%
Teemo	15.60%	15.74%	-0.14%	48.42%	51.79%	-3.37%
Thresh	17.60%	22.16%	-4.56%	49.04%	50.17%	-1.13%
Tristana	10.90%	11.63%	-0.73%	48.34%	49.06%	-0.72%
Trundle	4.00%	2.85%	1.15%	52.33%	52.18%	0.16%
Tryndamere	10.70%	8.50%	2.20%	54.72%	52.71%	2.01%
Twisted Fate	13.40%	13.79%	-0.39%	47.54%	48.25%	-0.71%
Twitch	4.30%	4.30%	0.00%	46.23%	47.23%	-0.99%
Udyr	10.80%	9.15%	1.65%	52.86%	53.35%	-0.49%
Urgot	0.80%	0.99%	-0.19%	47.20%	46.35%	0.84%
Varus	7.50%	6.87%	0.63%	51.22%	50.17%	1.05%
Vayne	24.40%	30.17%	-5.77%	48.43%	50.75%	-2.32%
Veigar	5.20%	4.15%	1.05%	50.54%	48.98%	1.56%
Vel'Koz	4.70%	3.16%	1.54%	52.67%	50.05%	2.62%
Vi	7.60%	6.65%	0.95%	51.37%	51.86%	-0.49%
Viktor	13.10%	14.66%	-1.56%	49.29%	48.50%	0.79%
Vladimir	6.00%	5.38%	0.62%	49.22%	48.54%	0.68%
Volibear	5.70%	4.87%	0.83%	52.20%	52.20%	0.00%
Warwick	11.00%	9.54%	1.46%	54.18%	53.34%	0.84%
Wukong	7.90%	7.81%	0.09%	52.00%	53.63%	-1.63%
Xerath	2.60%	2.44%	0.16%	51.34%	48.80%	2.54%
Xin Zhao	13.60%	11.09%	2.51%	53.82%	54.30%	-0.48%
Yasuo	19.90%	26.75%	-6.85%	50.06%	51.22%	-1.16%
Yorick	1.70%	1.55%	0.15%	47.68%	47.97%	-0.29%
Zac	2.20%	1.95%	0.25%	48.64%	46.95%	1.69%
Zed	11.00%	13.79%	-2.79%	46.95%	48.33%	-1.38%
Ziggs	4.20%	2.54%	1.66%	49.87%	48.97%	0.90%
Zilean	1.70%	1.47%	0.23%	48.77%	46.42%	2.35%
Zyra	3.20%	1.99%	1.21%	52.69%	53.89%	-1.20%

2. Blue side advantage

Blue side win rate for BMB: 52.9%
Blue side win rate for Blind Pick: 48.9%
Note that the discrepancy here may be caused by different matchmaking algorithms.

3. Game length

It seems that BMB games on average have comparable length to Blind Pick games. However, past the 20 minutes mark, it is possible that BMB games end slightly faster. Below is a density plot of game length of the two game modes.

Note: Player composition for the games above:

League Tier	BMB	Blind
Unranked	32.8%	37.7%
Bronze	18.4%	16.6%
Silver	27.9%	26.8%
Gold	13.1%	11.8%
Platinum	6.0%	5.5%
Diamond+	1.8%	1.6%

Solo Queue Ladder Analysis: How Long Does It Take for a Season 4 Gold Player to Return to Gold in Season 5?

One way to examine the effectiveness of the ladder is to look at how well a player can retain his rank after a reset. For example, if a player who is Gold is actually worthy of being Gold, we should expect to see this player to keep being Gold (or perhaps higher) after a ladder reset. Today, I am going to present some statistics on how the players' ranking have moved from late January 2015 (Season 4) to early July 2015 (mid-way of Season 5) - roughly a six months period.

First let's see how the players have moved. The table below presents the ladder transition from Season 4 to Season 5 for ~1 million players on the NA server who have ranked solo queue ladder records in both seasons.

For example, we see that after six months, 80.83% of Season 4 Bronze players remain in Bronze in Season 5; on the other hand, 53.94% of Season 4 Platinum players remain in Platinum whereas 10.6% of them are now Diamond or above.

Below is a more visual representation of the transition of these players.

Therefore, we see that more than half of the players who have records in Season 4 and played in Season 5 have retained their original rank (or better) after about six months. While this is interesting by itself, it does not take into account of the fact that many players are below their Season 4 ranking because they haven't played much. So for the next study, we will also take into the number of wins (number of games would be better, but they are not as readily available as number of wins via Riot API) into account. We are interested in, for example, how many wins it takes for a Season 4 Gold player to return to Gold (or higher) in Season 5?

As it turns out, the amount of wins required to return to Gold heavily depends on if the player was, say, Gold 5 or Gold 1. As you will observe below, a Gold 1 player from Season 4 will retain Gold in Season 5 far quicker than a Gold 5 player.

This is time-to-event plot similar to the one I used for the AFK analysis where our event of interest is to retain the same rank (e.g. Gold) from Season 4. The plot shows that the chance of a Season 4 Gold player staying below Gold in Season 5 (vertical axis) decreases as the player wins more games (horizontal axis). In particular, it suggests that a Gold 5 player in Season 4 has about 40% chance of staying below Gold after 100 wins (purple line); for Gold 1 players, this percentage is only about 2% (red line). Overall, as the player goes up within the Gold tier, he is able to more  quickly retain the Gold tier after a ladder reset. I believe this is good evidence that the League system is actually working fairly well.

For some of the technical notes on this entry, click here.

A Quick Note on AP Ezreal with Runeglaive

TL;DR: AP Ezreal's win rate is 7% higher with Runeglaive. Ranger's or Stalker's seems to be the more optimal choices than Skirmisher's (2% difference) for Ezreal's Smite.

Patch 5.12 introduced a new jungle item - Runeglaive - which has the interesting effect of improving AP Ezreal dramatically. I found ~10k games with mid lane AP Ezreal in Platinum-Diamond level NA ranked solo queue and found the following:

Playstyle	# of Games	# of Wins	Win Rate
No Smite	681	282	40.29%
Smite + Runeglaive	9654	4571	47.35%
Smite + No Runeglaive	86	27	31.40%

A simple two-sided proportions test of (No Smite) vs (Smite + Runeglaive) gives the p-value at 0.003062, which suggests the result is statistically significant despite the relatively tiny sample for No Smite.

Out of the players who did build Runeglaive, their choice for Smite is as follows:

Smite Choice	# of Games	Popularity	Win Rate
Ranger	3043	31.54%	48.04%
Stalker	2249	23.31%	48.33%
Skirmisher	4357	45.15%	46.36%

It seems that Skirmisher's does not perform as well as Stalker's or Ranger's (46% vs 48%); but Skirmisher's is definitely the more popular choice. Poacher's was used for less than ten games; the interested reader may attempt to compute the number of Poacher's bought using the data above. 

It's not surprising that AP Ezreal is doing a lot better with Runeglaive. Runeglaive gives AP Ezreal an AOE spell that can hit minions, thus vastly improving his waveclear - his traditional weakness. But it is quite amusing to see how a single item can dramatically change a champion from obscurity to LCS limelight.

Note:

1. The lane choice for the Ezreal player is determined using Riot's data.

2. The detection of AP Ezreal (as opposed to AD Ezreal) is by the proportions of magic and physical damage dealt to champions.

Twisted Treeline Hexakill Statistics (2015)

I gathered 95k Twisted Treeline Hexakill games in May 29th to May 30th, 2015.

1. Popularity

Champion	Popularity
Ekko	62.8%
Lux	38.4%
Ezreal	37.5%
Yasuo	30.7%
Teemo	29.4%
Ziggs	28.7%
Nidalee	28.2%
Ashe	26.4%
Jinx	21.3%
Fiora	21.0%
Bard	20.7%
Master Yi	20.4%
Blitzcrank	18.7%
Shaco	17.3%
Zed	16.5%
Wukong	16.4%
LeBlanc	15.9%
Jayce	15.5%
Katarina	15.2%
Riven	15.0%
Malphite	14.6%
Sona	14.6%
Viktor	14.0%
Talon	13.5%
Cho'Gath	13.3%
Fiddlesticks	13.3%
Morgana	13.2%
Azir	13.0%
Garen	12.9%
Darius	12.8%
Annie	12.8%
Fizz	12.7%
Heimerdinger	12.6%
Ahri	11.9%
Kog'Maw	11.7%
Vayne	11.7%
Vel'Koz	11.3%
Gnar	11.0%
Karma	11.0%
Veigar	10.9%
Orianna	10.7%
Lee Sin	10.5%
Karthus	10.4%
Gangplank	10.4%
Sion	10.3%
Vladimir	9.8%
Rengar	9.2%
Brand	8.9%
Akali	8.8%
Amumu	8.6%
Xin Zhao	8.2%
Rumble	8.1%
Sejuani	8.1%
Xerath	8.1%
Caitlyn	7.9%
Thresh	7.9%
Hecarim	7.6%
Varus	7.4%
Nautilus	7.4%
Miss Fortune	7.2%
Kalista	6.9%
Diana	6.9%
Tryndamere	6.6%
Singed	6.6%
Maokai	6.5%
Volibear	6.5%
Twisted Fate	6.3%
Kha'Zix	6.3%
Leona	6.3%
Pantheon	6.3%
Malzahar	6.2%
Alistar	6.2%
Cassiopeia	6.1%
Jax	6.1%
Gragas	6.1%
Kennen	6.0%
Sivir	5.9%
Lucian	5.9%
Mordekaiser	5.8%
Soraka	5.8%
Twitch	5.6%
Zyra	5.5%
Jarvan IV	5.2%
Nunu	4.8%
Irelia	4.6%
Tristana	4.6%
Swain	4.6%
Galio	4.6%
Vi	4.6%
Dr. Mundo	4.3%
Graves	4.0%
Lissandra	4.0%
Anivia	4.0%
Draven	3.8%
Rek'Sai	3.7%
Renekton	3.7%
Nami	3.6%
Lulu	3.5%
Shyvana	3.5%
Ryze	3.4%
Zac	3.4%
Zilean	3.3%
Nasus	3.3%
Janna	3.2%
Kayle	3.1%
Poppy	3.1%
Olaf	3.1%
Braum	3.0%
Rammus	2.9%
Warwick	2.9%
Udyr	2.9%
Shen	2.9%
Kassadin	2.8%
Elise	2.6%
Evelynn	2.6%
Quinn	2.5%
Aatrox	2.5%
Syndra	2.2%
Urgot	2.1%
Corki	2.1%
Trundle	2.1%
Yorick	1.8%
Taric	1.7%
Nocturne	1.5%
Skarner	1.0%

2. Win Rate

Only in non-mirror matchups.

Champion	Win Rate
Katarina	58.2%
Wukong	56.8%
Sion	56.6%
Lux	56.5%
Soraka	56.3%
Zyra	56.3%
Xerath	56.3%
Janna	56.0%
Sona	55.6%
Vel'Koz	55.2%
Galio	55.2%
Singed	54.7%
Leona	54.5%
Karthus	54.1%
Poppy	54.0%
Swain	54.0%
Talon	53.9%
Morgana	53.9%
Maokai	53.8%
Ziggs	53.8%
Taric	53.4%
Xin Zhao	53.3%
Fiddlesticks	53.3%
Malzahar	53.0%
Diana	53.0%
Nami	52.8%
Rammus	52.7%
Vladimir	52.6%
Kog'Maw	52.4%
Brand	52.3%
Master Yi	52.3%
Braum	52.3%
Karma	52.1%
Alistar	52.0%
Nautilus	51.9%
Cho'Gath	51.9%
Amumu	51.6%
Sejuani	51.5%
Anivia	51.4%
Fiora	51.3%
Ahri	51.3%
Heimerdinger	51.3%
Jarvan IV	51.3%
Shaco	51.1%
Trundle	51.0%
Annie	50.8%
Teemo	50.8%
Mordekaiser	50.7%
Pantheon	50.7%
Varus	50.5%
Nocturne	50.5%
Blitzcrank	50.5%
Irelia	50.4%
Jinx	50.3%
Zac	50.3%
Miss Fortune	50.1%
Garen	50.1%
Graves	50.1%
Ashe	50.0%
Caitlyn	49.9%
Rumble	49.8%
Darius	49.8%
Skarner	49.6%
Sivir	49.4%
Malphite	49.4%
Yorick	49.2%
Dr. Mundo	49.1%
Ryze	49.1%
Olaf	49.1%
Renekton	48.9%
Gangplank	48.9%
Zilean	48.9%
Hecarim	48.8%
Ekko	48.7%
Volibear	48.7%
Yasuo	48.7%
Lissandra	48.5%
Shen	48.5%
Vi	48.5%
Rengar	48.4%
Warwick	48.4%
Orianna	48.3%
Quinn	48.2%
Lucian	48.1%
Ezreal	48.1%
Gragas	48.0%
Kennen	47.9%
Fizz	47.7%
Lulu	47.7%
Draven	47.7%
Corki	47.5%
Jax	47.5%
Kassadin	47.3%
Aatrox	47.2%
Nunu	47.2%
Veigar	47.2%
Urgot	47.1%
Vayne	47.1%
Twitch	47.0%
Jayce	47.0%
Shyvana	46.8%
LeBlanc	46.8%
Tryndamere	46.8%
Twisted Fate	46.8%
Thresh	46.8%
Kayle	46.6%
Udyr	46.6%
Evelynn	46.5%
Tristana	46.4%
Cassiopeia	46.3%
Nidalee	46.3%
Rek'Sai	46.0%
Riven	45.7%
Nasus	45.6%
Syndra	45.2%
Gnar	45.1%
Viktor	45.1%
Kha'Zix	45.1%
Lee Sin	45.0%
Kalista	44.8%
Akali	44.8%
Zed	44.4%
Azir	42.6%
Bard	39.7%
Elise	37.5%

The statistics from last year can be found here. 

Note that one of the biggest differences from last year is the introduction of bans. This has presumably curbed the popularity of Katarina (73% -> 15%).