Information Sharing Using an Electronic Marketplace David Montana, Alice Leung and Marshall Brinn BBN Technologies

Overview Motivation Background Information sharing market A game: Find the Ring Experiments Conclusions

Information Sharing Requirements Lack of information sharing played an important part of intelligence failure prior to 9/11 –pieces of information existed, but could not piece them together Obstacles to information sharing –inertia of separation (cultural and technological) –threats to security and privacy “need to know” and paper trail have provided safeguards against too-wide dissemination example of problem: Robert Hanssen and FBI database Required: ability to share critical information across organizations fluidly as needed to detect terrorist plots but not too widely Proposed solution: well-regulated and restricted electronic market for buying and selling of intelligence information –incentivize and facilitate sharing while restricting information flow

Electronic Markets Background Much work and attention focused on electronic futures markets as method of predicting future events –proven effective for true/false and multiple-choice type predictions in places such as Iowa Electronic Markets and Hollywood Stock Exchange –lack ability for more free-form type of predictions (where cannot enumerate the possible outcomes) –information aggregation without sharing Electronic goods and services markets provide better model for information sharing –examples: eBay, monster.com and match.com –ability to quickly identify complementary needs among a pool of thousands of potential buyers and sellers, to establish a market, and to easily perform any transactions –easily auditable trail of transactions

Information Sharing Market: Framework Participants: buyers and sellers of information and data services –sellers submit sealed bids plus sealed descriptions of information –buyers submit sealed offers plus sealed descriptions of desired information Broker: matches buyers and sellers –if transaction realized, buyer receives copy of information from seller Large reward for piecing together pieces of information into coherent whole drives the market

Information Sharing Market: Issues Advantages over bulletin board or open database –incentivizes sharing rather than hoarding of information –discourages wanton gathering of information Large number of issues, including –security: with participants having different privileges –matchmaking: how to accomplish without revealing too much, particularly about what information is being sold –reputation: discouraging sale of bad information –economic (focus for this paper) what unit of payment? (e.g., fixed price vs. share of reward) price of a transaction? information about market to participants? information rights (does seller retain ability to sell again)? market dynamics? Investigate economic issues using a game that includes an information market

A Game: Find the Ring Suspects: R ring members among them –Large reward for player that identifies the members of the ring Players: each starting with $M and C clues Clues: partial information about which suspects in ring –Equivalence (A and B either both in or both out) –Anti-equivalence (either A or B in but not both) –Negative (A not in ring) Play proceeds in rounds, with each round consisting of two phases –players submit offers sell offers: minimum price plus clue buy offers: maximum price plus logical description of set of clues identification offers: guess the ring –broker resolves offers penalties (loss of money) for wrong identification reward for one (randomly chosen) correct id, and game over for each player, find best sell offer for one buy offer and split price for each player, find best buy offer for one sell offer and split price

Find the Ring (cont.) Stalemate if game proceeds N rounds without a transaction –stalemate is a bad outcome, since ring not found Information available to all players: –number of suspects, size of ring, number of players, etc. –summary of game state including “leader board” and number and average price of transactions last round Goals –individual: maximize money at end of game by collecting reward and/or by receiving more for selling clues than spent buying because reward not always given, not constant-sum game –game: maximize probability that ring found

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Strategies and Agents Two main components of strategy (analyzed in detail in paper) –which clues to try to buy important to know but specific to particular game –pricing on buy and sell offers focus of economic analysis relevance to information markets in general Implemented software agents to play the game –know which clues to buy –optimal pricing strategy depends on what other players doing provide small number of parameters that allow different components (buying, selling, stalemate backoff) of pricing strategy to vary between agents

Experiments Experimental method –select particular parameters for the game (number of players, number of suspects, size of ring, reward, starting money, number of initial clues of each type) and generate many different games from these parameters –try different mixes of agent strategies until converge on equilibrium where no player/agent can improve by varying strategy –measure properties of game/market, particularly fraction of time that ring found Vary parameters of game and see how this affects outcome

Results When sales competitive, prices low and market quickly proceeds to solution; conversely, when lack of sales competition (information monopoly), prices high and tendency to get stuck in stalemate When players have sufficient money (relative to reward), even in competitive case likely to reach solution eventually; however, when do not have sufficient money, tendency to get stuck in stalemate Change in broker mechanism will change specifics of the pricing strategies but will not change two basic conclusions above Conclusion: for situation where non-competitive sales and reward-to- capital ratio is high, need some mechanism for breaking the deadlock, e.g. providing a way to split any future reward

Conclusions Information sharing market provides a potential mechanism for information sharing that incentivizes and facilitates cooperation while maintaining a restricted and regulated flow of information Find the Ring game provides mechanism for studying some of the properties of an information sharing market in a controlled setting Using software agents and Find the Ring, we performed experiments investigating these properties and discovered some conclusions that can help general design of information sharing markets Much work remains to be done before can implement real-world information sharing market