A Fantasy Sports Wizard's Winning Formula | Hacker News Reader

A Fantasy Sports Wizard's Winning Formula

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62 pointssabon39 comments

It's been interesting to see the migration of online poker players over to daily fantasy sports (DFS). It definitely feels like the early days of online poker - tons of new sites popping up, heavy TV advertising, lots of new money coming into the "sport". I just started playing DFS this season and it's pretty addictive. Obviously, I don't think I'll be getting rich off it (the "I turned $5 into $50k" stories are just lottery winners essentially), but it's been fun (and a bit scary...) to get into the world of gambling without having to "know a guy". I've always played fantasy football for "fun" so it's been exciting to have a bit of cash on the line.

Daily fantasy is a whole new beast - it's at the intersection of data science, predictive modeling, quants, poker players, sports guys, Vegas, startups (FanDuel and DraftKings are killing it), bootstrapped entrepreneurs (RotoViz). You can make some serious money, put down $5 to make your Sunday afternoon more exciting, or play around with a new data modeling library on some interesting data.

There's a whole industry built around fantasy sports if you look just past the surface of ESPN Fantasy leagues. There are subscriptions sites offering premium content, people willing to sell you their Baynesian prediction models, ebooks about strategy, weekly video shows talking about the best plays. I read somewhere that fantasy football was actually worth more as industry than the NFL!

PS: If you want to try it out, here's a shameful affiliate link because I'm turning into a gamling degenerate: https://www.fanduel.com/?invitedby=swan3788&cnl=da

I've said the same thing about the early days of online poker to people putting money in those sites. Have fun and all but watch out for the regulatory hammer.

The online poker sites operated offshore, through high-risk credit card processors.

Fantasy sports markets, otoh, have Yahoo and CBS as operators (both take ~30% rake). FanDuel is processing a few hundred million through PayPal. Presumably, these companies are all paying taxes, so this time everybody's in on it.

I was thinking about this the other day and I decided that fantasy football is the most significant contributing factor in the crazy market share the NFL currently enjoys compared to the other major sports. If not for fantasy football, I don't think the NFL would be as overwhelmingly popular compared to the other sports as it is today. Because of fantasy football, nearly every game on television is watchable, because nearly every game has implications to the fantasy-viewer.

Of course, a lot of what makes fantasy football compelling to play is derived in part from what makes football compelling as a fan. 16 game seasons mean every game means something. One game a week, all on Sunday (until this dumb Thursday night football BS started), means there is a low overhead to team management. Multiple skill positions and multiple (interesting) ways to score (fantasy) points allows for varying strategies. Add all of those together and you end up with a game that is accessible to the masses, yet engaging and deep enough for those that choose to compete.

This is what ultimately holds back the other major fantasy leagues (NHL, NBA, MLB). Daily fantasy sports are a huge win for gaining back some of that market share, so it will be interesting how that affects actual viewership numbers in the future. Personally, I think the NBA is going to gain back some of the ground it has lost since the 90s.

Here's one thing I've been curious about for fantasy football.

Stats are obviously important, but I'm not sure they can ever replicate simply watching film. For instance, two weeks ago, Odell Beckham Jr of the NY Giants caught 5 catches for 44 yds and a TD. What the stat line doesn't tell you is that he actually smoked his defender a few times, was open in the endzone on a play, and if Eli had chucked it up to him or seen him in the endzone, ODB would have definitely had a couple more TDs, at least.

I don't know enough about fantasy basketball/baseball to say whether film is as powerful for those sports, but it seems like the best fantasy football analysts give heavy credence to film because it protects against overreacting to good/bad performances.

Another example - last year there was some player that saw a significant drop in touchdowns (I can't remember off the top of my head who it was). But after looking at film, it became apparent this player unfortunately kept getting tackled at the 1 yard line. Clearly, an anomaly.

Watching games/film definitely will show you stuff that the boxscore doesn't. Another recent example was a game in which Percy Harvin had 3 TDs called back on penalties. His stats didn't look great, but anyone watching the game knew that he busted out several big plays.

PS. Calvin Johnson is the player who was tackled at the 1.

That's right! I thought it was CJ but I thought I remembered hearing that about a running QB also (Cam maybe) so wasn't sure. And yes, agree about Harvin also.

Honestly, I've found /r/fantasyfootball has been a great resource.

This is a tough business to win as a player. The house is taking 8 - 10% rake meaning you have to have a 60% winning percentage just to break even. Much better business to be the house. Even if 30% of the players are highly skilled handicappers it's going to be very hard to consistently win this game. Sounds like fun to play, but as in all gambling enterprises, the real money comes from operating the casino, not playing there.

When I heard the fan duel ads on the radio and then saw it on ESPN, I couldn't believe that it was legal. Then I saw the law with the exception for fantasy sports and I was just super jealous of these legal sports book operators. Running an online sports book is like having a free money machine.

The rake is definitely unsustainable. Currently, its negative effects are masked by an influx of new players (Fanduel is growing roughly 300% per year [1]). But when that growth slows, the only people left to be ground into dust by the rake will be the longer-term player pool that once feasted on new players. One by one, they will lose their entire bankrolls, until the whole model collapses. They will eventually lower it, but it will almost certainly be too late by then.

[1] http://fanduel.com/investors

> The house is taking 8 - 10% rake meaning you have to have a 60% winning percentage just to break even.

That's only correct in a constant sized market. In a growing market with lots of new money coming in, its much easier to win. When growth stops, it becomes much more difficult. The vast majority of remaining players start losing, only the house (and maybe a couple sharks) can win consistently. Assuming a market in continual decline, eventually everyone loses (except the house).

Nate Silver devotes a chapter to this in The Signal and the Noise. He goes through the numbers, anecdotally supported by his experience during the online poker boom.

I have a lot of knowledge of advanced baseball statistic analysis, and played about $100 per day this year during the season, making a profit of ~$2000. This is my third straight winning season, but the first where I actually wrote code that spat out lineups.

I spent no money on data, everything you need is available for free.

If anyone has advanced knowledge of other sports and wants to collaborate, send me an email or tweet. Contact info in profile.

Here are my 2014 MLB results from Fanduel, the site I spent the majority of my time on:

  Entered  $15,128.00
  Won	   $17,022.04
  Profit   $1,894.04
  ROI      12.52%

Data: https://docs.google.com/spreadsheets/d/1rN8vhO1nZlojF-wiFSgq...

Interesting...I tried doing machine learning for daily fantasy baseball and it just didn't work. I wrote a scraper that put Fanduel results and contest payout structures into a database, then backtested against thousands of contests to see where I would have wound up had I played in those contests using projections from the machine learning algorithm. I figured I would eventually make the algorithm profitable. Unfortunately I was wrong. I couldn't find any combination of data to feed into the algorithm that consistently put me in the green. At least I wasn't actually playing and losing money.

I finally gave up after a few months. The scraper data was fascinating though....there were a few players consistently yielding 80%+ ROI across hundreds of entries.

I'm actually surprised you didn't overfit the data until the backtests showed you had a profitable algorithm. I bet most people would've done that.. I'm curious, what kind of algo were you training?

With Weka, I was able to test a wide variety of algos. When every Weka algo failed, I tried Google's prediction API with a wide variety of combinations of data and that failed as well. I thought for sure that one of them would work. Unfortunately, not a single one got me profitable over the long term. I could actually win slightly more than 50% of the time on 50/50 and "Double Up" contests, but that doesn't beat the rake.

Is there a reason you seem to favor head-to-head over, say, a 50/50 structure?

I tried to spread it around. My general strategy during the last month was: $40 in head-to-head (5 each of $1, $2, $5) $50 in double-ups (5 each of $5) $10-20 in big tournaments (usually just the $2 tournament with 10,000 players)

I put my best overall lineups in the head-to-head and double-up format, trying to limit too much exposure to one team unless it was an obviously superior play to do so, and 5-10 different lineups for the tournament structure, where I went with higher variance plays.

Interesting. My mental approach is more a grinder mentality where I spread my rosters across the 50/50s, avoiding the tournaments for the most part. I only enter the rosters I feel absolutely great about in those. This is all NFL though, so could be different.

I have never understood why daily games are legal. The outcomes can be determined by random events like injuries or the weather. How is this not gambling?

It is certainly gambling, but it's explicitly legal under certain conditions per the UIGEA. And there is definitely a skill component as well.

There were exemptions for fantasy sports made under the Unlawful Internet Gaming Enforcement Act. Basically, it's legal to 'gamble' on fantasy sports given the following conditions:

1. The prizes offered are established ahead of time (fixed prize pool, most sites implement this by capping the number of entries - and covering any overlay if not enough people enter)

2. The scoring is based on statistical results in multiple-real world games (none of the DFS sites allow you to 'bet' on a single games - the players must come from a pool of at least two NFL games)

3. Can't make "traditional bets" (spread, over/under)

(And less revelant to most people, you can't play fantasy for money if you are an member of the team - i.e. athletes can't 'bet' on themselves)

They are legal because the courts and legislation(such as the UIGEA) have deemed them to be legal.

I don't understand what seems to be a distinction between daily games and season-long leagues. Season-long outcomes are affected by injuries and other random factors as well(just ask anyone who drafted Adrian Peterson with their first pick this year).

It's legal because no major industry has turned their lobbying efforts on outlawing it yet. There's no clear philosophical line between gambling and, say, investing.. there's just (decreasingly) moral crusaders and (increasingly) interests who profit from keeping things illegal outside of their personal holdings.

This. Basically it doesn't compete directly with casinos (casinos bribe, I mean lobby politicians to pass anti-gambling laws).

Not trying to be snarky, but I never understood how the stock market works (it seems just as random).

In fact, the article has a paragraph where one player is offended that he might look like a gambler and is compared to a .. stock market investor? Trying to set fantasy sports apart from gambling didn't work for me that way..

I've always wondered, do you need a licensing deal to use individual player stats etc. to run a site like this? If not, it seems like the barrier to entry would be quite low and you wouldn't even really need the network effects that poker requires.

No. The stats seem to be in the public domain. See: http://www.silha.umn.edu/news/summer2009.php?entry=195089

NFL was thinking about saying they own the stats -- afterall it is their product. Needless to say that would require lots of lawyers but could potentially bring in huge new revenue stream.

I've been thinking about this recently. A developer could do so much better (he's still copying from spreadsheets). Who wants to put this guy out of business with me?

You'll surely be more efficient with handling data, but you don't have digital access to all the data you'd need.

For example, the chance that a player plays at all (if they are in questionable health) is one of the most important signals. But you can't just write a regression from past data on that player/team/coach. An intuitive guess from reading several media reports will be far for accurate. This guy is surely manually entering a "%chance of playing" driver into these models.

But, if you teamed up with a subject matter expert that fed meta-predictions into your model, you'd likely end up with better results.

> You'll surely be more efficient with handling data, but you don't have digital access to all the data you'd need.

It occurs to me that collating said data in an accessible format for a modest fee would be a pretty good low hanging fruit business idea. I'm sure there must be something like that out there but last time I looked into this, 2-3 years ago, I couldn't even get the NBA schedule in JSON or some other programming-friendly format, let alone things like injuries and lineup changes.

Sounds like an interesting project. Where would one even get this data from? Scraping ESPN is always an option (a painful one at that) but I'm not sure they would appreciate that.

Edit: After a quick Google search I found several data providers: http://www.quora.com/Are-there-any-APIs-with-game-schedules-...

Everything old is new again

http://en.wikipedia.org/wiki/STATS_LLC

"STATS LLC is a global sports statistics and information company – the company name originated as an acronym for "Sports Team Analysis and Tracking Systems". It was founded on April 30, 1981[1] by John Dewan,[2] who became the company's CEO. STATS was an outgrowth of the grassroots non-profit Project Scoresheet, a volunteer network created to collect baseball statistics, prompted by a suggestion made by Bill James, who later joined STATS for a time. In 1987, STATS developed a reporter network for Major League Baseball and provided research for NBC's postseason baseball coverage, and by 1989 was doing the same for ESPN's broadcasts.[1]"

The services are out there, and they ain't cheap.

I had fun trying my hand at generating NBA lineups earlier this year.[1] I'd love to give it another go (my email is in my profile).

1. https://news.ycombinator.com/item?id=7272365

A developer could do the parsing of the data better, but who's to say his spreadsheets (with I'm assuming graphs, color codes, etc) aren't providing the data visualization that makes the actual decision making clearer.

I don't know about putting him out of business, but I bet I could put myself in business with him.

I'm interested--send me a pm

I've been doing some models for live betting on ice hockey, but am now thinking of working on models for other sports as well. Would be nice to discuss about this and other ideas on sports betting and fantasy sports! My contact information is on my profile.

his competitive advantage is the algorithm not the tools he's using

I'd be interesting in putting heads together

email me at pwzst1@yahoo.com

Reply on news.ycombinator.com