340 likes | 478 Views
Smarter Markets: Bringing Intelligence into the Exchange Example: Smarter Prediction Markets. David Pennock Microsoft Research. NYSE 1926. http:// online.wsj.com /article/SB10001424052748704858404576134372454343538. html. NYSE 1987.
E N D
Smarter Markets: Bringing Intelligence into the ExchangeExample: Smarter Prediction Markets David PennockMicrosoft Research
NYSE 1926 http://online.wsj.com/article/SB10001424052748704858404576134372454343538.html
NYSE 1987 http://online.wsj.com/article/SB10001424052748704858404576134372454343538.html
NYSE 2006-2011 • 2011 Deutsche BörseAG • 2007 Euronext • 2006 Archipelago, ipo
2012 September107:23p.m. ET Between 3.0% and 3.7% chance
Goals for trade Efficiency (gains) Inidiv. rationality Budget balance Revenue Comp. complexity Equilibrium General, Nash, ... Design for Prediction
Goals for trade Efficiency (gains) Inidiv. rationality Budget balance Revenue Comp. complexity Equilibrium General, Nash, ... Goals for prediction Info aggregation 1. Liquidity 2. Expressiveness Bounded budget Indiv. rationality Comp. complexity Equilibrium Rational expectations Design for Prediction Competes with:experts, scoring rules, opinion pools, ML/stats, polls, Delphi
Goals for trade Efficiency (gains) Inidiv. rationality Budget balance Revenue Comp. complexity Equilibrium General, Nash, ... Goals for prediction Info aggregation 1. Liquidity 2. Expressiveness Bounded budget Indiv. rationality Comp. complexity Equilibrium Rational expectations Design for Prediction Competes with:experts, scoring rules, opinion pools, ML/stats, polls, Delphi
Why Liquidity? Low liquidity takes the prediction out of marketshttp://blog.oddhead.com/2010/07/08/why-automated-market-makers/ Between 0.2% and 99.8% chance
Why Expressiveness? • Call option and put options are redundant • Range bets require four trades(“butterfly spread”) • Bid to buy call option @strike 15 can’t match with ask to sell @strike 10 • Can’t set own strike • Bottom line: Lacks expressiveness
Why Expressiveness? • Dem Pres, Dem Senate, Dem HouseDem Pres, Dem Senate, GOP HouseDem Pres, GOP Senate, Dem HouseDem Pres, GOP Senate, GOP House... • Dem PresDem HouseDem wins >=270 electoral votesDem wins >=280 electoral votes...
Industry Standard • Ignore relationships:Treat them as independent markets • Las Vegas sports bettingKentucky horseracingWall Street stock optionsHigh Street spread betting
A Better Way(Or,... Bringing trading into digital age) • Expressiveness • Linear programming • Bossaerts, Fine, Ledyard: Combined Value Trading • http://bit.ly/multipm • Expressiveness + Liquidity • Automated market maker • Always quote a price on anything • Downside: requires subsidy/risk
Getting Greedy • Design a marketfor information on exponentially many things • “Combinatorial prediction market”
Combinatorial securities:More information, more fun • Payoff is function of common variables,e.g. 50 states elect Dem or Rep
Combinatorial securities:More information, more fun • Dem will win California
Combinatorial securities:More information, more fun • Dem will lose FL but win election • Dem will win >8 of 10 Northeastern states • Same party will win OH & PA PA OH
Combinatorial securities:More information, more fun • There will be a path of blue from Canada to Mexico WA OR
Some Counting 54 “states”: 48 + DC + Maine (2), Nebraska (3) 254= 18 quadrillion possible outcomes 2254 1018008915383333500distinct predictionsMore than a googol, less than a googolplex NOT independent
A tractable combinatorial market maker using constraint generationACM EC 2012 MIROSLAV DUDÍK,SEBASTIEN LAHAIE,DAVID M. PENNOCK Thanks: David Rothschild, Dan Osherson, Arvid Wang, Jake Abernethy, Rafael Frongillo, Rob Schapire
Combo Prediction Markets:More Info Gory detailsWhat is (and what good is) a combinatorial prediction market? http://bit.ly/combopm More accessibleGuest post on Freakonomics http://bit.ly/combopmfreak