Interactive explainer

Why NBA teams lose on purpose — and what could actually stop them

Every spring, teams at the bottom of the standings quietly start resting their best players, losing close games, and chasing bad draft odds. This isn't an accident. It's game theory.


We'll walk through the math behind tanking: what makes it individually rational, why the 2019 lottery reform didn't fix it, and why a system borrowed from women's hockey might be the most elegant solution nobody's talking about.

Each section has live sliders and simulations. Play with them. The argument is in the numbers.

Stage 01 — The incentive

Losing is worth a lot of money

Before we add rivals, imagine you're a GM of a lottery team with no realistic shot at the playoffs. You have one decision: field your best roster, or quietly lose games to improve your draft odds.

U = α · D̂(expected draft pick value) + β · R(season revenue)

The problem is the relative size of these terms. Revenue sharing means the difference in income between a 20-win team and a 36-win team is surprisingly small. But the expected value of a high draft pick, especially in a superstar year, is enormous. And critically, the value isn't primarily in year-over-year revenue. It's in franchise valuation.

When LeBron James left Cleveland in 2010, the Cavaliers' franchise value dropped from $476M to $355M in a single year. Over the next four years without him, the franchise grew just $39M, to $515M. When LeBron returned in 2014, the valuation jumped to $915M within twelve months. By the time he left again in 2018, the Cavs were worth $1.325 billion. That's $810M in franchise value gained in four years, versus $39M in the four years prior. Revenue sharing smooths out the annual income difference between winning and losing teams. It does nothing to close that gap.
Single team payoff model
α draft weight2.0
β revenue weight1.0

Even at equal weights, tanking comes out ahead for a bottom-10 team. The revenue delta is small; the draft value delta is large. This is the foundation of everything that follows.

Stage 02 — The prisoner's dilemma

When everyone tanks, everyone loses

Now add a rival team. You're both rational. You both see the same incentives. What happens?

This is a textbook prisoner's dilemma. The Nash equilibrium is (Tank, Tank), every time. The 2019 lottery reform attempted to compress odds and push teams toward a "coordination zone." See how well it works:

Note: not every team tanked pre-2019 even when that was the dominant strategy. Some franchises prioritized fan experience, coaching development, or simply disagreed on the math. The model shows the rational incentive structure; reality is messier. That messiness is actually what prevents total league collapse under the current system.

2-team payoff matrix · underlined = best response · green = Nash equilibrium
α draft weight2.0
β revenue weight1.0
Lottery system
Rival: tankRival: compete
You: tank
You: compete

Now watch all 30 teams evolve over 82-game seasons. Each team updates its strategy based on the payoffs it observes. The two panels run simultaneously under pre-2019 and post-2019 rules using the α/β values you set above. Hit Auto-run.

30-team league simulation · 82-game seasons
Tank Compete
Speed
PRE-2019 LOTTERY
Season 0
POST-2019 LOTTERY
Season 0

Under pre-2019 rules the league almost always converges to near-universal tanking within a few seasons. Post-2019 can create a mixed stable state, but only when the ratio α/β stays below roughly 3. When draft value weight significantly outweighs revenue weight, which is the realistic case for small-market teams in a superstar year, watch the reform fail. The 2019 reform assumed teams are sensitive to marginal odds differences. In a superstar draft year, they aren't.

A useful thought experiment: what if draft position had nothing to do with record, a pure lottery where every team had equal odds? Tanking would disappear entirely. If you can't improve your odds by losing, there's no incentive to lose. You still pay the revenue cost of a bad season; you just stop getting the compensating draft benefit. That baseline matters because it isolates where the problem actually lives, not in the draft itself, but in the specific link between losing and lottery position. The hockey model attacks that link directly. Compressing the odds, as the 2019 reform did, merely weakens it.

Stage 03 — The full league

When the prize gets bigger, the problem gets worse

Tanking pressure doesn't stop at the worst records. It cascades up the standings, all the way to teams fighting for the final playoff seed.

The play-in introduced a wrinkle the 2019 reform didn't anticipate. A team on the playoff bubble faces a real calculation: fight for a play-in spot that likely ends in early elimination with no lottery ticket, or miss the playoffs entirely and land in the lottery. In a superstar draft year, the lottery upside of missing the playoffs can outweigh the playoff upside of the play-in, especially for a team with no realistic path to advance. The play-in was designed to keep more teams relevant. It accidentally created a zone where falling short of it is strategically attractive.

The 2025 Dallas Mavericks made this concrete. They missed the playoffs at 39 wins, won the lottery, and selected Cooper Flagg. A near-.500 team walked away with a generational pick.

But the play-in is a symptom of a deeper problem. Recall the franchise value swings from Stage 1: LeBron's return to Cleveland added $810M in four years. A single generational player doesn't just improve a team. It transforms the entire financial trajectory of a franchise. And unlike large-market teams, small-market franchises can't attract that player through free agency; the draft is their only realistic shot at one. So as the perceived value of any given draft class rises, the incentive to tank doesn't just persist, it intensifies. The basic two-term utility function doesn't capture this. We need a third term:

U = α · D̂ + β · R + γ · S(superstar franchise uplift)

The γ · S term captures something the basic model misses entirely: the one-time, non-recurring franchise value explosion that comes from landing a generational player. This isn't revenue; it's the difference between a franchise worth $800M and one worth $3B. It's local media rights, jersey sales, national TV appearances, and sponsorship premiums that compound for years. For small-market teams with no free-agency appeal, the draft isn't one pathway to a superstar; it's the only one, which makes γ enormous and essentially permanent if you hit.

Curry was the 7th pick. Giannis was 15th. Neither was seen as a likely franchise cornerstone at the time, but the team picking 8th couldn't draft Curry, and the team picking 16th couldn't draft Giannis. Every lottery spot is a potential miss at a player who could have been yours. That's why even marginal improvements in odds, the difference between 9th and 12th in the lottery, get treated as high-stakes decisions.

2-team payoff matrix · underlined = best response · green = Nash equilibrium
α draft weight2.0
β revenue weight1.0
γ superstar term0.0
System
Draft year
Rival: tankRival: compete
You: tank
You: compete

Now watch the core dynamic across all three systems. Key experiment: switch to Superstar year and raise γ to 2–3. Under pre-2019 and post-2019 NBA rules that produces near-universal tanking. Under the hockey model the same γ reinforces competing, because superstar value now flows through winning games on the elimination table, not losing them.

30-team simulation · pre-2019 vs post-2019 vs hockey model
Tank Compete
Speed
NBA PRE-2019
Season 0
NBA POST-2019
Season 0
HOCKEY MODEL
Season 0
Stage 04 — The fix

Women's hockey figured this out already

Once you're mathematically eliminated from the playoffs, you start accumulating points on a separate league table. The team with the most points gets the #1 pick. Every win after elimination directly improves your draft position.

This completely inverts the incentive for eliminated teams. And worse teams get naturally biased toward better picks, not through lottery odds, but through geometry. A team eliminated in February gets ~25–30 games on the table. A team that just misses the play-in gets maybe 5. That gap is the mechanism. No randomness required.

For teams on the playoff bubble, the hockey model doesn't dramatically change the strategic calculus: whether they fight for the play-in or fall short of it, they accumulate zero table games either way. What changes is the upside. Under the current system, missing the play-in in a superstar draft year still carries a lottery ticket and a real chance at the #1 pick. Under the hockey model, that jackpot doesn't exist. There's no consolation prize for a near-.500 team. The only path to a top pick is being eliminated early and then winning games.

The closer the tiers are in elimination timing, the flatter the effective odds. The more spread out, the stronger the bias toward worse teams:

Season timeline — elimination table games earned
Regular season Elimination table
Adjust elimination timing
Effective draft odds — elimination table share

Each tier's share of total table games = their effective draft odds. No lottery. No randomness.

Expected outcomes by tier

Notice what happens when you push all three tiers to nearly the same elimination date: the odds flatten toward equal. Pull them apart and the early lottery tier's advantage compounds naturally. The system is self-correcting.

One implementation challenge worth noting: in a 30-team league, schedule difficulty varies considerably across the remaining games of an eliminated team. A team eliminated with 24 games left might face 22 playoff-caliber opponents mostly on the road; another eliminated with 4 games left might face the weakest teams in the league at home. Remaining schedule strength isn't random, and in a system where post-elimination wins directly determine draft position, that asymmetry matters. Any serious implementation would need to either randomize end-of-season scheduling for eliminated teams or publish remaining schedules transparently, so the process can't be quietly tilted in any direction.

The hockey model isn't without its complications. But it puts the incentive back where the soul of the game lives. No fan wants to root for their team to lose.
Stage 05 — The what-if

The last three drafts, rewritten

If the hockey model had been in place for the 2023, 2024, and 2025 drafts, who would have gotten which pick?

This is a counterfactual. Teams would have behaved differently under different rules, so the actual elimination dates and win totals would shift. But applying the hockey model retroactively to real seasons gives an honest sense of how the pick order changes, and whether the system actually biases top picks toward the worst teams the way it's designed to.

Play-in teams are treated as eliminated on the date of their play-in loss with zero remaining games.

Draft year

A few things jump out across all three years. Post-elimination winning performance, not regular-season record, is what drives draft position under the hockey model. San Antonio accumulated 9 table wins in 2024 with only 22 regular-season wins and would have picked first. Houston led with 7 table wins in 2023 and would have done the same. Detroit had the worst record in both of those years and lands mid-table both times, because being eliminated early only creates the opportunity to accumulate table wins; you still have to take it.

The zero table wins cases are the starkest. Any team that finishes the season without accumulating a single post-elimination win, whether they narrowly missed the play-in or missed the playoffs entirely, falls to the bottom of the draft table regardless of record. In 2025, Dallas missed the playoffs at 39 wins and won the lottery outright, getting the #1 pick. Under the hockey model, zero table wins guarantees a team will not be picking anywhere near the top of the draft.

The hockey model doesn't eliminate tanking by penalizing it. It eliminates tanking by making winning the only lever that positively moves draft position. So fans of every team, for every game that remains, have a reason to want their team to win.
Model details & derivations
↓ full analysis (.ipynb)
Utility function
U(s) = α · D̂(s) + β · R(s) s ∈ {Tank, Compete} · α = draft weight (slider) · β = revenue weight (slider)
Hardcoded parameter values
StrategyD̂(s) — draft valueR(s) — revenue
Tank7220
Compete5038

Draft values are normalised relative to a 50-unit baseline (the CC payoff in Stage 02). Revenue is modelled as a fraction of league revenue share; tanking teams earn modestly less via gate receipts but near-equal TV distributions under the current revenue-sharing structure.

Dominance condition
Tank is individually optimal iff U(T) > U(C):   α·72 + β·20 > α·50 + β·38 α·(72 − 50) > β·(38 − 20) α·22 > β·18 α/β > 18/22 ≈ 0.818
Tanking is individually rational for any α/β > 0.82. In a superstar draft year, estimates of α/β for small-market teams routinely exceed 2–3. The 0.82 threshold is almost never binding in practice.
Assumptions & limitations

Utility is additively separable and linear in α, β. The γ·S franchise-value term (introduced in Stage 03) is excluded here, which understates the true tank incentive. Revenue sharing is treated as complete; in reality gate revenue creates a small additional cost to losing that this model somewhat underweights.

Payoff function — 2-player symmetric game
π(sᵢ, sⱼ) = α · D(sᵢ, sⱼ) + β · R(sᵢ) D(sᵢ, sⱼ) = expected draft pick value given both teams' strategies
Draft pick values D(sᵢ, sⱼ)
Rival: TankRival: Compete
You: Tank5275
You: Compete3050

Post-2019 (flattened odds): TT=52, TC=62, CT=38, CC=50 — the reform compresses the TC/CT gap, reducing the reward to unilateral tanking and the punishment for unilateral competing.

R(Tank)R(Compete)
2065
Nash equilibrium conditions

For a symmetric 2-player game, (s*, s*) is a Nash equilibrium iff s* is a best response to s*.

// (Tank, Tank) is NE iff Tank is BR to Tank: π(T,T) ≥ π(C,T) α(DTT − DCT) ≥ β(RC − RT) = β · 45   Pre-2019: α · (52−30) ≥ β · 45 → α · 22 ≥ β · 45 → α/β ≥ 2.045 Post-2019: α · (52−38) ≥ β · 45 → α · 14 ≥ β · 45 → α/β ≥ 3.214
// (Compete, Compete) is NE iff Compete is BR to Compete: π(C,C) ≥ π(T,C) α(DTC − DCC) ≤ β · 45   Pre-2019: α · (75−50) ≤ β · 45 → α · 25 ≤ β · 45 → α/β ≤ 1.800 Post-2019: α · (62−50) ≤ β · 45 → α · 12 ≤ β · 45 → α/β ≤ 3.750
Equilibrium regions by α/β
System(C,C) onlyCoordination zone(T,T) only
Pre-2019< 1.80∅ (gap → mixed NE)> 2.045
Post-2019< 3.213.21 — 3.75> 3.750
The 2019 reform raised the (T,T) NE threshold from 2.045 to 3.214 and created a coordination zone of width ~0.54 α/β units. The pre-2019 gap (1.80–2.045) had no pure NE at all; the reform converted that to a coordination zone and extended it.
Social optimum vs. Nash
WCC = 2 · π(C,C) = 2 · (α·50 + β·65) WTT = 2 · π(T,T) = 2 · (α·52 + β·20)   WCC > WTT iff β · 45 > α · 2 → β/α > 0.044 // Cooperation is socially superior for essentially all α, β > 0.
Classic prisoner's dilemma structure: cooperation maximises joint welfare but is individually irrational at any realistic α/β. The 2019 reform narrows the region where defection is individually rational but does not eliminate it.
Three-term utility function
U(s) = α · D̂(s) + β · R(s) + γ · S(s) γ = superstar franchise-value weight · S = one-time franchise uplift term
S payoff values by system and draft year
SystemDraft yearS(Tank)S(Compete)ΔS = ST − SC
NBANormal202+18
NBASuperstar502+48
HockeyNormal216−14
HockeySuperstar232−30
Effect of γ on the (Tank, Tank) Nash equilibrium condition
Full condition with three terms: α(DTT − DCT) + γ · ΔS ≥ β · 45   // NBA superstar year (ΔS = +48): α · 22 + γ · 48 ≥ β · 45 ← γ amplifies tanking incentive   // Hockey model, normal year (ΔS = −14): −α · 36 − γ · 14 ≥ β · 45 ← never satisfied for α, β, γ > 0
Under the hockey model, (Tank, Tank) is not a Nash equilibrium for any positive α, β, γ. The same γ that makes tanking worse under NBA rules makes competing better under hockey rules — because superstar upside flows through winning post-elimination games, not losing during the regular season.
Assumptions

S values are heuristic calibrations, not direct empirical estimates. The franchise-value uplift in LeBron's Cleveland return (~$810M over four years) is well-documented, but mapping that to a normalised S unit requires an analyst-specified scale. The qualitative claim — ΔS is large and positive under NBA rules, large and negative under the hockey model — is robust to reasonable choices of scale. The exact γ thresholds at which the NE flips are scale-dependent.

Elimination table mechanics
Tier i is eliminated at game eᵢ, where eᵢ < 82   Table games earned: gᵢ = 82 − eᵢ // post-elimination wins on the table determine draft pick order
Effective draft odds (deterministic, no lottery)
pᵢ = gᵢ / Σₖ gₖ // tier i's share of total table games = their effective draft odds
Structural properties
Monotonicity: ∂pᵢ/∂eᵢ < 0 — earlier elimination strictly improves odds, all else equal.
Self-correction: as eᵢ → eⱼ for all i, j, odds flatten toward 1/n. As eliminations diverge, early-tier advantage compounds multiplicatively. The system automatically scales with how spread out the league's records are.
Necessary and sufficient condition for top pick: a team must (a) be eliminated early and (b) accumulate the most post-elimination wins. Neither condition alone is sufficient. Early elimination creates the opportunity; winning after elimination takes it.
Default tier values (sliders at starting position)
TierElim. game eᵢTable games gᵢOdds pᵢ
Early lottery523060.0%
Mid lottery671530.0%
Late lottery77510.0%
Total50100%
Comparison with post-2019 NBA lottery (top-3 slots)
SystemWorst team3rd-worst teamRandomness
NBA lottery (post-2019)14.0%14.0%Yes
Hockey model (default tiers)60.0%10.0%No

The hockey model produces steeper odds than the NBA lottery — but those odds are earned through play and fully deterministic. A team cannot get lucky into the #1 pick; it must earn it by both losing the regular season and winning after elimination.

Implementation note — schedule strength

Remaining schedule strength is not controlled for in this model. A team eliminated at game 52 may face 20+ playoff-calibre opponents, largely on the road; one eliminated at game 77 may play weaker teams at home. Any real implementation would need either schedule randomisation for eliminated teams, or transparent schedule publication to prevent quiet manipulation of remaining strength-of-schedule.

Logit best-response dynamics

The simulation uses logit (softmax) updating rather than pure best-response. This models bounded rationality: teams are more likely to play better strategies, but noise prevents full convergence to a deterministic equilibrium in early seasons. The temperature parameter τ controls how much noise.

Expected utility given population state
Population state at season n: pT(n) ∈ [0,1] = fraction of league tanking   Ū(T, pT) = α[pT · DTT + (1−pT) · DTC] + β · RT + γ · ST Ū(C, pT) = α[pT · DCT + (1−pT) · DCC] + β · RC + γ · SC
Logit update rule
// each team independently redraws its strategy each season:   P(Tank | pT, τ) = σ(ΔŪ / τ) = 1 / (1 + exp(−(ŪT − ŪC) / τ))   // σ(·) = logistic function · τ = temperature · ΔŪ = Ū_T − Ū_C
Temperature schedule
τₙ = max(4, 20 − 1.2 · n) // n = season number, starting at 0   n = 0: τ = 20.0 (noisy — high exploration) n = 13: τ = 4.0 (near-rational best response) n ≥ 13: τ = 4.0 (fixed — residual mixing floor)
At τ → 0: pure best-response. σ(ΔŪ/0) approaches a step function. Teams always play the dominant strategy.
At τ → ∞: uniform mixing. σ → 0.5. Teams ignore payoffs entirely.
The cooling schedule models a league that starts with heterogeneous, noisy beliefs and converges toward rational play over ~13 seasons. The floor τ = 4 preserves residual mixing to prevent the simulation from locking into a single strategy artificially.
Nash equilibrium vs. QRE vs. simulation
ConceptRationalityEquilibrium type
Nash equilibriumPerfectBest-response fixed point
QRE (τ fixed = 4)BoundedLogit fixed point: p* = σ(ΔŪ(p*)/4)
Simulation (τ cooling)Bounded, improvingConvergence path to near-QRE
Mean-field approximation

Each team computes expected utility using the league-wide fraction pT as a sufficient statistic for opponent strategy distribution. This mean-field assumption suppresses team heterogeneity (market size, roster age, draft pick inventory, ownership preferences). All 30 teams face identical payoff structures in the model. Real tanking decisions vary substantially across franchises for reasons this model does not capture — which is partly why real leagues never fully converge to the Nash equilibrium the model predicts.