Parlay EV Question

[oVan]

I know that parlays are an -EV bet except for extreme circumstances. For instance, a 3 team parlay paying 6:1, assuming the game lines are correct, is a -EV bet. How would the EV be calculated?

Edit:

Is it something like this?

If spread is accurate, then odds at -100 are:
0.5*0.5*0.5 = 0.125 = 7:1

but pays only 6:1 thus you lose the difference.

Or is it even worse, like this with bets at -110:

(0.5*10/11)^3 = 0.0939 = 9.6:1

So the only time a parlay is a good bet is if it pays 7:1 (or 9.6) or better?

[Daliman]

Without getting too far into details I don't specifically know anyways, parlays can be good bets, and actually at a certain win % become more profitable than straight betting. I'm not quite certain why professional sports bettors don't use them more often, ( hell maybe they do), but I'd guess it's usually either variance reduction, ignorance of the %'s, or just a problem getting games to parlay properly.

[Thremp]

Typically odds on parlays are worse than the best number you can find while lineshopping, which makes them unfeasible. Ideally if you could parlay your best prices, you would.

[thelyingthief]

the nominal value of a parlay is figured e.g. for a three-teamer: a = ( the original wager + the winnings of bet 1 ) parlayed into the second bet, b = ( a + winnings of second ), parlayed into the last leg, c = ( b + winnings of third ).

your odds should be:
( c - original bet ) / original bet

used to be, the books would pay out on a two-teamer at a rate = to the nominal rate of a two teamer, and cost < than the total vig on two seperate bets. this, of course, is now mythology.

i use parlays when two events are playing concurrently; and despite the warnings you encounter against their use, have a significant edge on the play. were i anything other than a discretionary player, i would not play them. that is, i handicap games. i particularly like to play money line dogs into a strong choice. of course, i seldom play them, usually 1 for every 10-15 plays.

as an aside, it has been my experience that those who warn against the parlay aren't very good players, (that is, have no judgment) and usually depend on arbitrage for their plays. i have never known an arbitrager who made a good wage arbitraging football only, although including baseball and basketball in their mix may be another story. most arbitragers of my acquaintance thrived on the NBA.

i had denver at -14 MONEYLINE into the over in their first super bowl win.

2200->~50K. a sweet moment, indeed.

tlt

[Austiger]

There is no EV difference between betting games straight or parlaying them IF you are getting correct odds. There is a lot of variance though, obv. If you can't calculate the odds yourself, you probably aren't good enough with numbers to be gambling profitably anyway, but you can always just google 'parlay calculator.'