What is an edge in sports betting?

What is an edge in sports betting? Rain Man. Let's play some cards here. You want to hit? You've got eighteen. Sir, you have eighteen — you don't want to hit. Hit me. — He's hitting eighteen. — Hit me. You took my queen, Ray. I needed that queen. — Sir, please don't touch the cards. There's lots of them. Lots and lots of them. — Hold on here for a second. I'm going to double down. Queen. Queen. Yes, sir. Gotta love this town. You want to bet one chip or two chips, Ray? — Two. [Two chips. The card comes — and they win.] That was Rain Man — Raymond counting the cards, hitting eighteen on purpose, and telling Charlie when to bet two chips instead of one. When you know more than the price does, that's an edge. An advantage: your honest estimate of the true chance is better than what the price implies. On The Cold Line, edge is the gap between our model's line and the market line — and we name the side the value is on. In plain terms: the price says one thing, and you have a good reason to believe another. The gap is the edge. It pays over many bets, not on any one night. “Model has them at fifty-five percent — that’s a real edge at minus one-ten.” Let's use this example. The Bills are minus one-ten. That price breaks even at fifty-two point three eight percent — one-ten divided by two-ten. Say your honest number is fifty-five percent. Risk one hundred ten dollars: fifty-five percent of a hundred-dollar win is fifty-five dollars; forty-five percent of a hundred-ten-dollar loss is forty-nine fifty. That's plus five dollars and fifty cents per bet — about five percent of the stake. The edge is the gap: fifty-five versus fifty-two point three eight. An edge is an estimate, not a promise. Even a real one loses plenty of single bets. Lines move and books differ. Nothing here is a guarantee or a command to bet — it's how the number works.