PROP BETS 101

What Is a Prop Bet?

A proposition bet (prop bet) is a wager on a specific statistical outcome within a game — not the game's final result. Instead of betting on who wins, you're betting on what a specific player will do.

Examples:

• Aaron Judge OVER 0.5 Home Runs (+310)
• Paul Skenes OVER 6.5 Strikeouts (+120)
• Juan Soto OVER 1.5 Total Bases (+115)
• Patrick Mahomes OVER 279.5 Passing Yards (-115)

Prop bets are where information asymmetry lives. The sportsbook sets lines for hundreds of players daily. They can't be experts on all of them. A bettor who deeply understands how Statcast data translates to HR probability — or what a pitcher's swinging-strike rate means for K upside — has a genuine edge.

How American Odds Work

All odds on PropBetEdge are displayed in American format. Here's how to read them:

Positive Odds (+)

A plus sign means the outcome is the underdog. The number tells you how much profit you make on a $100 bet.

Negative Odds (−)

A minus sign means the outcome is the favorite. The number tells you how much you need to bet to win $100 profit.

Implied Probability

Every set of odds contains an implied probability — the book's estimate of how likely the outcome is.

The formula: For positive odds (+X): 100 / (X + 100). For negative odds (−X): X / (X + 100).

Expected Value (EV)

Expected Value is the most important concept in prop betting. A bet is profitable long-term only if it has positive expected value (+EV).

OVER vs UNDER — Which Side Has Edge?

The public loves OVER bets. More action, more excitement, rooting for something to happen. Books know this and shade their lines accordingly — the OVER is often slightly more expensive than it should be.

This creates a systematic edge on UNDER bets in many markets. But PropBetEdge's model doesn't pick sides by feel — it compares implied probability to our Poisson model probability and takes whichever side has true positive EV.

What Makes a Good Prop Bet

1. 1

   Positive Expected Value

   Your probability estimate is higher than what the odds imply. Without this, you're just gambling.

2. 2

   Real Information Advantage

   You know something the line doesn't fully price in — a late lineup change, weather shift, umpire assignment, or Statcast trend the book hasn't adjusted for.

3. 3

   Favorable Variance Profile

   Low-variance props (total bases, hits) vs. high-variance props (HR) have different risk profiles. HR props are binary and explosive; TB props are smoother and easier to model.

4. 4

   Sharp vs. Square Lines

   Lines that haven't moved much since open are often sharper. Lines that the public has bet heavily are often soft. PropBetEdge surfaces where our model disagrees with the market.

The Four Markets on PropBetEdge

⚾ Home Run Props

Will a batter hit at least one home run? Modeled using xSLG, barrel%, exit velocity, and park factor. Judge at +310 means the market says 24.4% — our model might say 30%. That gap is the edge.

📊 Total Bases

The sum of a batter's bases: 1B=1, 2B=2, 3B=3, HR=4. A common line is 1.5 or 2.5. Models use xwOBA, contact quality, and opposing pitcher EV allowed to predict TB distribution.

⚾ Strikeout Props (K Props)

How many strikeouts will a pitcher record? Driven by stuff quality (velo, movement), swinging-strike rate, and the opposing lineup's K rate. PropBetEdge's K-Score (0-100) summarizes this quickly.

🎯 Hits Props

Will a batter get at least one hit? Or OVER/UNDER a hits total. Smoother distribution than HR, easier to model with xBA, contact rate, and opposing pitcher groundball/flyball tendencies.

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