La scommessa come bussola

Il miglior modo per prendere le decisioni è essere informati e il miglior modo per informarsi è conoscere quello che gli altri sanno. Robin Hanson parte da questo assunto per proporre una soluzione che corregga gli errori decisionali più comuni. Il suo saggio si intitola “Decision Markets”.

Agire sulla testa delle persone è decisivo:

The human part of any large intelligent system is by far the most intelligent part. As long as this remains true, the biggest system advancements will come from aids that fill big holes in human abilities, rather than from artifacts that stretch engineers’ abilities. Consider Post-it Notes or, better yet, plain paper notepads. These probably seemed like trivial ideas, but they turned out to be terribly useful…

Condividere le informazioni non è facile come si pensa: chi deve offrire info non sempre ha i giusti incentivi  e chi deve ottenerle spesso è riluttante poiché teme di guastare i suoi pre-concetti:

… Consider, for example, a clearly important policy question such as, How would crime rates change if more citizens could legally carry hidden guns?… I suspect that the existence of such divergent opinions reflects the fact that we suffer from a serious failure to share information… The real problem is not finding more words, but judging who really knows about the topic and whether these experts are saying what they know. We are in many ways bit-full, yet information-poor…

Che fare? La proposta:

… I suggest that speculative markets are a neglected way to help us find out what people know. Such markets pool the information that is known… Speculative markets are decentralized and relatively egalitarian, and they can offer direct, concise, timely, and precise estimates in answer to questions we pose. These estimates are self-consistent across a wide range of issues and respond quickly to new information. They also seem to be cheap and relatively accurate

Per capire come funziona, torniamo al problema delle armi:

… Imagine that we created markets where people could bet on future crime rates, conditional on allowing or not allowing more hidden guns. That is, if the market prices predicted that murder rates would be 10 percent higher should a certain hidden-gun bill pass, then anyone who thought this estimate too high could easily identify a particular profitable trade… if market prices said that crime rates would be 10 percent higher given more hidden guns, most nonexperts would accept this estimate as our “best answer” or as a neutral “consensus.”…

L’incentivo all’onestà intellettuale è palese:

… Speculators, in turn, would have a clear incentive to be careful and honest in contributing what they know and in judging what advocates know… speculators must “put their money where their mouth is.”

C’è pur sempre bisogno di un terzo:

… Next, you must choose some particular trusted third party who will finally declare a murder rate M within [0,1] and determine whether bill B passed…

E i rischi di sabotaggio?

… Finally, you have to decide how much to subsidize this market. If interest in your topic is strong enough, simply creating these markets might induce people to trade in them. Failing that, sufficient interest might be induced if someone committed to make a policy choice based on the market estimate… You can also safely and directly subsidize a market to induce more participation…

Abbiamo fatto le esempio del nesso tra armi e crimini, in realtà le materie dove gli speculatori potrebbero dire la loro sono parecchie:

… Murder rates-with or without capital punishment? • Average mortality rates-with or without national health insurance? • Health-care spending-with expanded or curtailed use of health maintenance organizations? • Employment change-raise minimum wage or rescind NAFTA? • Global sea-level and temperature changes-impose or not impose a carbon dioxide tax? • Military casualties-with a Republican or a Democratic president? • Stock prices-with a Republican- or Democrat-controlled U.S. Congress? • World per capita food consumption-raise or lower average tariffs? • Student test scores-with or without school choice or voucher reform? • Future national economic growth-raise or lower interest rates, or with or without an education subsidy?…

Ma le speculazioni di mercato hanno esiti affidabili?

decades of research on the efficiency of financial markets have found little price-relevant information that is not reflected in market prices… Any inefficiencies seem to be weak and to go away with publicity, because they represent a profit opportunity. If you think the current price is too low, you expect to profit by buying now and selling later, and buying now will raise the price… For example, orange juice futures prices have been shown to improve on government weather forecasts… Also, markets where traders can bet on election results predict vote totals better than opinion polls

Chissà come mai ma quando in ballo c’è il nostro denaro molti bias cognitivi si dileguano e la qualità delle scelte migliora sensibilmente:

… while most traders tended to suffer from cognitive biases such as expecting others to agree with them, the most active traders were not biased this way-and active traders set the prices. Speculative markets thus seem to induce the real experts to self-select and participate more…

I mercati devono essere sufficientemente “densi” per funzionare, in questo senso le sperimentazioni messe in campo al momento sono abbastanza incoraggianti:

… Older economics writings sometimes give the impression that speculative markets will not function unless you have thousands of traders frequently trading millions of dollars worth of goods. Recent Web markets, however, clearly show that markets can be much smaller and slower than this…

Con il web i costi della “speculocrazia” si abbassano notevolmente e l’istituto della “scommessa” migliora la sua fama man mano che nei vari campi emerge la sua utilità sociale.

…  Until the last few centuries, the cost of simply handling trades was enough to sharply limit the number of speculative markets that could be made widely available. Yet today, ebay.com routinely sells $10 items by having a handful of people bid a few times each over a period of a week… More important, most speculative markets are now illegal. The short history of financial market regulation is that everything was once illegal until limited exemptions were granted for specific purposes… Gradually, exceptions were granted for what came to be seen as worthy purposes, such as teaching people about horses (horseracing) or raising state revenue (lotteries)… Stocks were allowed for the purpose of capitalizing firms… insurance was allowed to let individuals hedge risks… commodity futures and financial derivatives were allowed to let firms hedge more risks…

Una via per testare i “Decision Market” potrebbe essere quella di consigliarne l’adozione all’interno delle corporation:

… how can we test prototypes if IA markets are generally illegal? Well, there is one plausible loophole (besides offshore gambling), which I have saved for those of you who are still reading this far: internal corporate markets…

E in effetti qualcuno già traffica con questi strumenti:

… several companies, including Hewlett-Packard and Siemens, have begun experimenting with real-money internal speculative markets for estimating things such as future sales…

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