Back to The Negative Binomial Distribution
Chapter 9ExerciseCalculator

Practical Workflow and Exercises

Build a negative binomial prop calculator

Practical Workflow and Workbook Exercises

You now have all the pieces. Let's put them together into a repeatable workflow for Negative Binomial prop betting, then test your skills with comprehensive exercises.

The 8-Step Negative Binomial Workflow

Key Insight

The Complete Process:

  1. Identify the Prop Type (count-based: TDs, Ks, threes, goals)
  2. Gather Historical Data (15-20 games minimum)
  3. Calculate VMR (if < 1.3, use Poisson and stop here)
  4. Calculate r using method of moments: r = μ² / (Variance - μ)
  5. Adjust μ for Matchup (keep r constant—it reflects player's nature)
  6. Calculate Probabilities using NEGBINOM.DIST
  7. Compare to Market and Calculate EV
  8. Bet if +EV and Within Bankroll (Kelly sizing from Chapter 5)

Workflow Decision Tree

START: Count-based prop (TDs, Ks, 3PM, goals, etc.)
  │
  ▼
Gather 15-20+ games of data
  │
  ▼
Calculate VMR = Variance / Mean
  │
  ├── VMR < 1.3 ──────► Use POISSON
  │                        │
  └── VMR ≥ 1.3 ──────► Calculate r = μ² / (Var - μ)
                           │
                           ▼
                     Adjust μ for matchup
                     (keep r constant)
                           │
                           ▼
                     Calculate p = r / (r + μ)
                           │
                           ▼
                     Use NEGBINOM.DIST for probabilities
                           │
                           ▼
                     Compare to market implied probability
                           │
                           ├── Edge > 0 ──► Calculate Kelly, place bet
                           │
                           └── Edge ≤ 0 ──► No bet

Sport-Agnostic Principles

Regardless of which sport you're betting, these principles apply universally:

1. Overdispersion Is Real and Exploitable

Many players are boom-or-bust, not consistent. Books often assume consistency (Poisson). Your edge comes from identifying overdispersion and using Negative Binomial to get more accurate probabilities for extreme outcomes.

2. Extreme Outcomes Are Where the Value Lives

Negative Binomial's fatter tails mean higher probabilities for 0 occurrences and 3+ occurrences. These are often mispriced, especially 3+ outcomes at long odds (+800 to +1500). The market tends to underprice tails because they use Poisson or don't fully account for variance.

3. Adjust μ, Not r, for Matchups

The dispersion parameter r reflects a player's inherent boom-or-bust nature. It doesn't change game-to-game. Only adjust μ for matchup quality, pace, game script, etc.

4. Process Over Results (Even More Important)

Negative Binomial props have even higher variance than Poisson props. A 3+ TD bet at 11.5% probability will lose 88.5% of the time. You'll have brutal losing streaks. Trust the math over 100+ bets, not 10 bets.

5. Convergence at Middle Outcomes

For moderate μ (0.8-1.2) and moderate r (1.0-2.0), Poisson and Negative Binomial often give similar probabilities for middle outcomes (1-2 occurrences). The edge is in the extremes—0 or 3+.

Cross-Referencing Previous Chapters

Note

Cross-referencing Chapter 5 (Bankroll Management): With precise Negative Binomial probabilities, you can now implement Kelly criterion for boom-or-bust props. An 18.5% probability on a +800 line suggests a Kelly bet of about 8% of bankroll, but most pros use fractional Kelly (25-33%) to reduce variance, bringing it down to 2-3% of bankroll.

Note

Cross-referencing Chapter 8 (Poisson): You now know when to use Poisson (VMR ≈ 1.0) and when to use Negative Binomial (VMR > 1.3). The decision tree is simple: Calculate VMR first, then choose your distribution. This prevents systematic errors in your probability estimates.

Note

Cross-referencing Chapter 7 (Normal Distribution): For high-volume stats (100+ yards, 25+ points), the Normal distribution is still your best tool. Negative Binomial is for low-volume, count-based props where 0, 1, 2, 3 are the common outcomes. Know which tool to use for which situation.

Your Statistical Toolkit Summary

DistributionBest ForKey Assumption
NormalHigh-volume continuous (yards, points)Symmetric, bell-shaped
PoissonConsistent count data (VMR ≈ 1)Variance = Mean
Negative BinomialBoom-or-bust count data (VMR > 1.3)Variance > Mean

Workbook Exercise 9.1: Build a Negative Binomial Calculator

Create an Excel sheet for Negative Binomial props with these columns:

ColumnHeaderFormula/Content
APlayerName
BStat TypeTDs, 3PM, Ks, etc.
CHistorical Mean=AVERAGE(data)
DHistorical Variance=VAR.S(data)
EVMR=D2/C2
FCalculated r=C2^2/(D2-C2)
GMatchup AdjustmentMultiplier (e.g., 1.10)
HAdjusted μ=C2*G2
Ip Parameter=F2/(F2+H2)
JLine0.5, 1.5, etc.
KOddsAmerican odds
LP(Over)=1-NEGBINOM.DIST(INT(J2),F2,I2,TRUE)
MMarket Implied=IF(K2<0,ABS(K2)/(ABS(K2)+100),100/(K2+100))
NEdge=L2-M2

Test Case: Boom-or-bust RB, Rushing TDs

  • Historical Mean: 0.85
  • Historical Variance: 1.03
  • VMR: 1.21
  • r: 4.00
  • Matchup Adjustment: 1.12 (plus matchup)
  • Adjusted μ: 0.95
  • Line: 0.5
  • Odds: -130 (Over)

Expected Output:

  • P(1+ TDs) = 56.4%
  • Market Implied = 56.5%
  • Edge = -0.1% (no bet)

Workbook Exercise 9.2: Overdispersion Detection Template

📝 Exercise

Instructions

Analyze these three players and determine which distribution to use for each:

Player A (Consistent): 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0

Player B (Moderate): 2, 0, 1, 0, 2, 1, 0, 1, 0, 2, 1, 0, 1, 0, 2, 1, 0, 1, 0, 1

Player C (Extreme Boom-or-Bust): 3, 0, 0, 0, 2, 0, 0, 3, 0, 0, 0, 2, 0, 0, 3, 0, 0, 2, 0, 0

Calculate Mean, Variance, VMR, and r for each.


Workbook Exercise 9.3: Poisson vs. Negative Binomial Comparison

📝 Exercise

Instructions

For a boom-or-bust player with μ = 1.30 and r = 0.67, calculate probabilities using both Poisson and Negative Binomial for k = 0, 1, 2, 3, 4. Identify where the +EV opportunities exist.

Hint: For Negative Binomial, p = r / (r + μ) = 0.67 / (0.67 + 1.30) = 0.340


Workbook Exercise 9.4: Full Prop Analysis Workflow

📝 Exercise

Instructions

Complete a full analysis for a hypothetical backup RB with the following:

Historical Data: μ = 0.75, Variance = 1.20

Market: 2+ Rushing TDs at +800

Matchup: Plus matchup, increase μ by 20%

Bankroll: 100 units

Walk through all 8 steps of the workflow and determine your bet size.


Moving Forward

The Negative Binomial distribution completes your toolkit for count-based props. You now have:

  • Poisson for consistent players (VMR ≈ 1.0)
  • Negative Binomial for boom-or-bust players (VMR > 1.3)
  • Normal for high-volume continuous stats (Chapter 7)

Key Insight

Remember the key principles:

  • Test for overdispersion using VMR
  • Use Negative Binomial when VMR > 1.3
  • Adjust μ for matchups, keep r constant
  • Extreme outcomes (0 or 3+) are where the value lives
  • Requires 15-20 games of data for reliable r estimates
  • Variance is brutal—trust the process over 100+ bets

But props don't exist in isolation. A quarterback's passing touchdowns correlate with his receivers' receiving touchdowns. A team's total points correlates with their star player's scoring props. In Chapter 10, we'll explore correlation and covariance—the mathematical tools for understanding how props move together. This becomes essential for Same Game Parlays and multi-prop strategies.

Negative Binomial Calculator

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