Thread by @JustinFreeman18

Wanted to thread🧵some thoughts on parlays📜and round robins🐦 in sports betting. What are they, when to use them, etc.

Let's start by unlearning a few things.

Parlays are surefire ways to spot newbs with no clue what "expected value" is. They are sucker bets... OR ARE THEY? 👇

What makes a parlay #bad? Well, if you're like me, the parlay=bad mantra has been drilled in for quite some time. And generally, for good reason.

Why? Because most single item sports bets are bad in the first place. Multiplying them together in fact makes them worse.

Joe Public thinks the Dolphins are stone cold locks to cover 3.5 against the Jets on the road. He bets into -110 in an efficient market with no real method to generate an edge, meaning he likely has a 50% chance of being right but needs a 52.38% chance to beat the vig.

So what happens when Joe has similar takes for 3 other games and wants to string together a 4-leg parlay? He deserves +1500 if each game is a coin flip, but at -110 each leg, he'll get +1228.

Compounding -EV decisions = bad. Of course. So how can we make them #good?

Well, if multiplying -EV bets is #bad, then multiplying +EV bets can be #good. And if they are *very* +EV, they can be *very very* #good.
Think about player props. If I had you bet all 1,000 player props on the board, you'd likely hit on roughly half - maybe better.

But the books can't effectively monitor *all* these props, so if I told you to pick your fav 20 out of the 1,000 available, you'd likely hit on 60% or better. And if you can hit each of those at -110, then you have 20 +EV bets. A 60% hit rate means the price *should* be -150.

Now what happens when you parlay 4 of these +EV bets at -110 that should be at -150? As we mentioned earlier, a 4-leg -110 parlay will pay +1228. But in this case, it *should* pay +671. HELLO!

This is crazy value. It is the compounding interest of sports betting.

This brings us to round robins. What *is* a round robin anyway?

A round robin is basically just an easy way to take a pool of bets and hit all possible parlays. Imagine we really like 4 player props tonight. How many different parlays could you make out of those 4 bets?

You could make:
- 1 4-leg parlay
- 4 3-leg parlays
- 6 2-leg parlays
So there are 11 total parlays available. Most books will allow you to apply a flat bet amount to each parlay with their round robin tool. So what happens if we do $10 each and end up going 3-1 on our 4 choices?

For starters, we put up $110 (11 parlays at $10 each) and it turns out we win $68.93. We win $519.85 if we go 4-0 and we lose $73.55 at 2-2 or $110 at 1-3 or worse. But check out the EV overall if we can consistently get it in good. 41.9% EV on every dollar we can get down. Wild.

So while you won't go broke simply taking your 14% EV on every 60% hit rate prop you can find, you likely should be compounding your edges. Multiplication is your friend.

H/T to @AwesemoDFS who I first noticed doing this with some monster parlays and round robins - seemed crazy at first, but given the source, I had to give it more thought.

https://twitter.com/AwesemoDFS/status/1459544358479409156?s=20

TLDR; You probably have an edge on player props if chosen selectively. Compound your edges with parlays and round robins. Ditch the "parlays are sucker bets" mantra when you can quantify your edge.