CBI

Competitive Balance Index

Measures league parity within an era. Lower concentration of championships and more varied playoff teams indicates higher competitive balance.

Formula

100 - (Championship Concentration x 30) + (Playoff Team Variance x 25) + (Win Distribution Evenness x 25) + (Unique Finalists x 20)

Championship Concentrationera_championship_concentration (30%)

Unique Playoff Teamsera_unique_playoff_teams (25%)

Win Distribution Evennessera_win_distribution_evenness (25%)

Unique Finalistsera_unique_finalists (20%)

Grade Scale

A+

A-

B+

B-

Benchmarks

Small Ball Era72.6

Jordan Era 1990s72

2000s Post-Jordan Era71.9

1990s Bulls Dynasty70.7

Stern Era 1984-201458.3

Data Sources

Basketball-Reference.comNBA.com/stats

Grade Interpretations

A+

Maximum parity. Any team can win the championship in a given year.

High competitive balance. Multiple legitimate contenders each season.

A-

Good balance. Several strong teams with competitive playoffs.

B+

Moderate balance. A few dominant teams but competitive middle class.

Below-average balance. Clear separation between contenders and pretenders.

B-

Low parity. Dominated by 1-2 super teams with predictable outcomes.

Competitive Balance Index Leaderboard

#	Entity	Score	Grade	Interpretation
	Small Ball Eraera	72.6	A-	Good balance. Several strong teams with competitive playoffs.
	Jordan Era 1990sera	72.0	A-	Good balance. Several strong teams with competitive playoffs.
	2000s Post-Jordan Eraera	71.9	A-	Good balance. Several strong teams with competitive playoffs.
4	2020s International Eraera	71.0	A-	Good balance. Several strong teams with competitive playoffs.
5	1990s Bulls Dynastyera	70.7	A-	Good balance. Several strong teams with competitive playoffs.
6	Larry Bird Magic Johnson Eraera	69.5	A-	Good balance. Several strong teams with competitive playoffs.
7	Shaq Kobe Lakers Dynastyera	69.5	A-	Good balance. Several strong teams with competitive playoffs.
8	Warriors Dynasty 2010sera	68.9	A-	Good balance. Several strong teams with competitive playoffs.
9	1980s Showtimeera	68.9	A-	Good balance. Several strong teams with competitive playoffs.
10	1970s ABA Merger Eraera	68.4	A-	Good balance. Several strong teams with competitive playoffs.
11	Bad Boys Pistons Eraera	67.5	A-	Good balance. Several strong teams with competitive playoffs.
12	2010s Superteam Eraera	66.9	A-	Good balance. Several strong teams with competitive playoffs.
13	Load Management Eraera	65.5	A-	Good balance. Several strong teams with competitive playoffs.
14	Hand-Checking Eraera	64.5	B+	Moderate balance. A few dominant teams but competitive middle class.
15	Expansion Era 1970sera	60.9	B+	Moderate balance. A few dominant teams but competitive middle class.
16	Bubble Era 2020era	58.6	B+	Moderate balance. A few dominant teams but competitive middle class.
17	Stern Era 1984-2014era	58.3	B+	Moderate balance. A few dominant teams but competitive middle class.
18	1960s Celtics Dynastyera	57.8	B+	Moderate balance. A few dominant teams but competitive middle class.
19	Pre-Three-Point Eraera	57.5	B+	Moderate balance. A few dominant teams but competitive middle class.
20	Silver Era 2014-Presentera	56.8	B+	Moderate balance. A few dominant teams but competitive middle class.
21	Bill Russell Dynasty Eraera	56.8	B+	Moderate balance. A few dominant teams but competitive middle class.
22	Big Three Celtics Eraera	56.3	B+	Moderate balance. A few dominant teams but competitive middle class.
23	Player Empowerment Eraera	55.6	B+	Moderate balance. A few dominant teams but competitive middle class.
24	Seven Seconds or Less Eraera	53.7	B	Below-average balance. Clear separation between contenders and pretenders.
25	Lob City Clippers Eraera	53.4	B	Below-average balance. Clear separation between contenders and pretenders.
26	1950s NBAera	53.1	B	Below-average balance. Clear separation between contenders and pretenders.
27	Heatles Eraera	51.9	B	Below-average balance. Clear separation between contenders and pretenders.
28	Grit and Grind Grizzlies Eraera	51.6	B	Below-average balance. Clear separation between contenders and pretenders.
29	Allen Iverson Culture Eraera	49.7	B	Below-average balance. Clear separation between contenders and pretenders.
30	Kareem Skyhook Eraera	49.0	B	Below-average balance. Clear separation between contenders and pretenders.
31	LeBron Era 2010sera	42.9	B-	Low parity. Dominated by 1-2 super teams with predictable outcomes.
32	Superteam Eraera	41.1	B-	Low parity. Dominated by 1-2 super teams with predictable outcomes.
33	Warriors Splash Bros Eraera	40.9	B-	Low parity. Dominated by 1-2 super teams with predictable outcomes.
34	Integration Era 1950sera	32.1	C	Below-average balance. Clear separation between contenders and pretenders.
35	George Mikan Eraera	31.0	C	Below-average balance. Clear separation between contenders and pretenders.
36	Pre-Shot Clock Eraera	30.4	C	Below-average balance. Clear separation between contenders and pretenders.
37	Wilt Chamberlain Scoring Eraera	28.3	C	Below-average balance. Clear separation between contenders and pretenders.