Revealing Penalty Bias Within the NHL

Bias is something inherent to humanity–either consciously or subconsciously. But does this bias extend to the NHL?

Using data from Hockey Reference, starting from the 2014 regular season, our goal is to reveal any potential patterns in penalty bias, defined as the difference between the average number of penalties a team’s opponents receives versus the average number of penalties the team receives. A positive penalty bias score indicates more favorable treatment from the referees, and the opposite for a negative score.

This content seeks to inform Ontario sports betting enthusiasts about the various factors that could affect NHL odds.

Key Findings:

🏒Tampa Bay Lighting have been penalized the most since 2014 (4.27 per game)

🏒Vegas Golden Knights have been the least penalized since 2017 (3.33 per game)

🏒 Columbus Blue Jackets have are the least penalized since 2014 (3.52 per game)

🏒 Tripping has been the most common penalty since 2014 (15.82% of all penalties)

🏒 Chicago Blackhawks have experienced the most favorable penalty bias

🏒Anaheim Ducks have received the least favorable penalty bias

Most Penalized NHL Teams Since 2014

Penalties. They can really throw things off for any team that starts getting into a rhythm. But which NHL team has received the most penalties since 2014?

The team that has been the least penalized since 2014 is the Blue Jackets. Despite having lower average penalties per game, Golden Knights and Seattle Kraken have only been active since 2019 and 2021 respectively.

Rank	Team	Average Penalties Per Game
1	Tampa Bay Lightning	4.27
2	Florida Panthers	4.21
3	Ottawa Senators	4.10
4	Philadelphia Flyers	4.01
5	Colorado Avalanche	3.99
6	Nashville Predators	3.97
7	Winnipeg Jets	3.95
8	Calgary Flames	3.94
9	Pittsburgh Penguins	3.89
10	Boston Bruins	3.87
11	Minnesota Wild	3.84
12	Washington Capitals	3.81
13	Anaheim Ducks	3.79
14	Vancouver Canucks	3.77
15	Montreal Canadiens	3.77
16	Arizona Coyotes	3.76
17	Detroit Red Wings	3.74
18	Dallas Stars	3.72
19	New York Rangers	3.71
20	Los Angeles Kings	3.70
21	St. Louis Blues	3.69
22	San Jose Sharks	3.69
23	Toronto Maple Leafs	3.64
24	Edmonton Oilers	3.63
25	Chicago Blackhawks	3.61
26	New Jersey Devils	3.60
27	Buffalo Sabres	3.59
28	Carolina Hurricanes	3.52
29	New York Islanders	3.52
30	Columbus Blue Jackets	3.52
31	Seattle Kraken	3.48
32	Vegas Golden Knights	3.33
	Overall Average	3.77

NHL referees clearly become quite whistle happy when it comes to Tampa Bay Lightning. Tampa has averaged 4.27 penalties per game since 2014.

Compared to the relatively well favored Columbus Blue Jackets across the same time period–the Blue Jackets only get penalized 3.52 times per game.

Most Popular Penalty Types

Tripping makes up a whopping 15.82% of all penalties since 2014–that’s 100158 individual penalties.

Hooking closely follows, with 13,133 penalties being attributed to this foul type.

Rank	Penalty Reason	Number of Penalties
1	Tripping	15,849
2	Hooking	13,133
3	Roughing	10,143
4	Interference	9,005
5	Slashing	8,534
6	Holding	8,470
7	High Sticking	7,403
8	Fighting	6,709
9	Cross Checking	4,369
10	Delay of Game	3,336
11	Too Many Men on the Ice	2,330
12	Misconduct	1,707
13	Boarding	1,572
14	Unsportsmanlike Conduct	1,548
15	Holding the stick	706
16	Elbowing	577
17	Goaltender interference	577
18	High Sticking – Double Minor	498
19	Holding Stick	426
20	Delaying Game-Puck over glass	276
21	Embellishment	269
22	Game misconduct	267
23	Illegal Check to Head	263
24	Closing hand on puck	252
25	Charging	227
26	Instigator	217
27	Kneeing	194
28	Interference on breakaway (Penalty Shot)	180
29	Interference – Goalkeeper	169
30	Face-off Violation	131
31	Instigating	103
32	Illegal Equipment	92
33	Match penalty	76
34	Hooking on breakaway	68
35	Diving	51
36	Broken stick	33
37	Delaying Game-Smothering puck	31
38	Clipping	30
39	Instigator – Misconduct	29
40	Tripping on breakaway	29
41	Delay Gm – Face-off Violation	25
42	Concealing Puck	24
43	Abuse of Officials	23
44	Throwing stick	17
45	Spearing	16
46	Too many men on ice	16
47	Bench Penalty	15
48	Interference in crease (Penalty Shot)	14
49	Goalie Interference	13
50	Holding on breakaway	12
51	Slash on breakaway	11
52	Checking from behind	9
53	Abusive language	8
54	Illegal stick	8
55	Interference – Throwing object (Penalty Shot)	8
56	Delaying Game – Smothering Puck	6
57	Goalie leave crease	6
58	Delaying Game-Ill. play goalie	5
59	Head butting	5
60	Covering puck in crease	4
61	Goaltender leaving crease	4
62	Unsportsmanlike Conduct – Coach	4
63	Spearing (maj)	3
64	Throw object at puck	3
65	Butt ending	2
66	Butt ending (maj)	2
67	Illegal substitution	2
68	Interference – Displacing net (Penalty Shot)	2
69	Interference (maj)	2
70	Objects on Ice	2
71	Aggressor	1
72	Check From Behind	1
73	Coach/Mgr on ice	1
74	Illegal Substitution – Bench	1
75	Instigator – Face Shield	1
76	Kneeing (maj)	1
77	Net displaced	1
78	Roughing – double minor	1
	Grand Total	100,158

Overall Penalty Bias

Looking at the total number of penalties given against the opponent measured against the total number of penalties given against the team in question, we managed to find that some teams experience positive, or negative bias when it comes to penalties.

Overall, our analysis found that 14 teams had a negative penalty bias–meaning that they received more penalties during each game compared to their opponents.

17 teams had a positive penalty bias–meaning that referees tend to blow the whistle more against the opposing team.

Since 2014, the Chicago Blackhawks have received the most bias in their favor (8.03). They’re followed by Colorado Avalanche (5.09) and then by the Vegas Golden Knights (4.83).

On the other end of the spectrum, Anaheim Ducks receive the most bias against them (-13.39), by some margin. The next team to them are the Boston Bruins (-5.20), followed by the Arizona Coyotes (-5.11), now the Utah Hockey Club.

Team	Penalties against opponent	Total Committed Penalties	Penalty Bias	Penalty Bias Difference
Chicago Blackhawks	3094	2855	239	+8.03
Colorado Avalanche	3424	3254	170	+5.09
Vegas Golden Knights	1780	1696	84	+4.83
Carolina Hurricanes	3009	2902	107	+3.62
Calgary Flames	3383	3274	109	+3.27
Pittsburgh Penguins	3320	3215	105	+3.21
Minnesota Wild	3293	3203	90	+2.77
Florida Panthers	3605	3513	92	+2.58
San Jose Sharks	3165	3088	77	+2.46
Buffalo Sabres	3074	3000	74	+2.44
Philadelphia Flyers	3437	3362	75	+2.21
Seattle Kraken	852	835	17	+2.02
New York Islanders	3011	2956	55	+1.84
Tampa Bay Lightning	3654	3589	65	+1.79
Dallas Stars	3182	3127	55	+1.74
Winnipeg Jets	3394	3389	5	+0.15
Toronto Maple Leafs	3116	3115	1	+0.03
New York Rangers	3182	3182	0	0.00
Ottawa Senators	3520	3522	-2	-0.06
Nashville Predators	3394	3396	-2	-0.06
Los Angeles Kings	3172	3179	-7	-0.22
Detroit Red Wings	3200	3210	-10	-0.31
St. Louis Blues	3173	3187	-14	-0.44
Vancouver Canucks	3227	3276	-49	-1.51
Washington Capitals	3260	3340	-80	-2.42
Edmonton Oilers	3120	3200	-80	-2.53
New Jersey Devils	3082	3168	-86	-2.75
Columbus Blue Jackets	3017	3125	-108	-3.52
Montreal Canadiens	3228	3397	-169	-5.10
Arizona Coyotes	3221	3390	-169	-5.11
Boston Bruins	3316	3493	-177	-5.20
Anaheim Ducks	3253	3720	-467	-13.39

Methodology

We’ve taken on the exciting task of analyzing penalty bias in the NHL, using data from hockey-reference.com starting from the 2014 season.

Our goal is to reveal any potential patterns in penalty bias, defined as the difference between the average number of penalties a team gives to its opponents versus the average number of penalties it receives. A positive penalty bias score indicates more favorable treatment from the referees, and the opposite for a negative score.

• Data Collection: We used Python to gather detailed game data, focusing on penalties from the 2014 regular season onwards.
• Data Transformation: We applied specialized techniques to clean and transform the raw data, making it ready for analysis.

Key points of analysis:

• Most common penalty reason across all teams.
• Teams that suffered the most penalties overall.
• Teams that committed the most penalties overall.
• Teams that suffered the most penalties per season.
• Teams that committed the most penalties per season.

You can find the full dataset here.