Prediction Markets Definitions – REDUX REDUX

No GravatarI would like to comment on the post from the Hatena Diary blog. (By the way, please note that my URL has changed, because I corrected one word in the post title. Sorry for the inconvenience.)

#1. Speculation-oriented prediction markets/exchanges: TradeSports, BetFair.

#2. Hedging-oriented prediction markets/exchanges: HedgeStreet and all the Chicago exchanges that will do binary, European call options.

#3. Forecast-oriented prediction markets/exchanges: Iowa Electronic Markets, AS CLAIMED BY THESE SCHOLARS WHOSE TASK WAS TO CONVINCE THE CFTC TO GRANT THEM A NO-ACTION LETTER. (They would have not gotten it, had they emphasized &#8220-speculation&#8221-. And, of course, &#8220-hedging&#8221- was out of question.) It&#8217-s a &#8220-claim&#8221- that might be discussed, since we&#8217-ve seen that TradeSports-InTrade is a much more powerful predictive tool for the US elections. Ditto for BetFair for U.K. elections.

#4. Decision-oriented prediction markets/exchanges: I would put here the kind of stuff that Robin Hanson is so excited about.

#5. Entertainment-oriented prediction markets/exchanges: Hollywood Stock Exchange, Washington Stock Exchange, Inkling, NewsFutures.

#6. Education-oriented prediction markets/exchanges: The Iowa Electronic Markets fits here, partially, regarding the use that professors around the country make of their markets in classrooms.

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– I disagree with Google in #4. Maybe the Google internal prediction markets would fit in #3.

– I disagree with NewsFutures in #3 &#8212-I acknowledge (at least partially) the predictive power of play-money prediction exchanges, of course.

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Should we judge markets/exchanges on INTENTIONS or on RESULTS? I don&#8217-t give a damn that TradeSports-InTrade and BetFair were created for speculation– if they have better predictive power than IEM, I&#8217-m fine with them. Ditto for the HSX. I don&#8217-t give the first fig that it was created as an entertainment tool. It&#8217-s the best forecasting tool for the movie business, period.

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For the links to the prediction exchanges, see CFM.

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Previous Blog Posts:

Prediction Markets DEFINITIONS – not a “taxonomy”

Professor Robin Hanson’s draft definitions is validated by professor Eric Zitzewitz.

Prediction Markets Definitions – REDUX

Prediction Markets Definitions – by Robin Hanson – 2006-11-21

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Addendum: Robin Hanson has posted a comment&#8230-

“Oriented” is not clear enough for my tastes. Is this about trader motives? Trader results? Price results? Exchange motives?

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My Answer: I meant &#8220-exchange motives&#8221-. [&#8230- See my comments. &#8230-] But now that I think of it, another classification taking account of the &#8220-price results&#8221- makes more sense.

Previous blog posts by Chris F. Masse:

Gartmans Rules of Trading

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My favourite Thanksgiving tradition, from trading God Dennis Gartman

1. Never, Ever, Ever, Under Any Circumstance, Add To A Losing Position&#8230- not ever, not never! Adding to losing positions is trading&#8217-s carginogen- It is trading&#8217-s driving-while intoxicated. It will lead to ruin. Count on it!

2. Trade Like A Wizened Mercenary Soldier: We must fight on the winning side, not on the side we may believe to be correct economically.

3. Mental Capital Trumps Real Capital: Capital comes in two types-mental and real, and the former is far more valuable than the latter. Holding losing positions costs measurable real capital, but it costs immeasurable mental capital.

4. This Is Not A Business Of Buying Low And Selling High- It is, however, a business of buying high and selling higher. Strength tends to beget strength, and weakness, weakness.

5. In Bull Markets One Can Only Be Long or Neutral , and in bear markets, one can only be short or neutral. This may seem self-evident- few understand it however, and fewer still embrace it.

6. &#8220-Markets Can Remain Illogical Far Longer Than You Or I Can Remain Solvent.&#8221- These are Keynes&#8217- words and illogic does often reign, despite what the academics would have us believe.

7. Buy Markets That Show The Greatest Strength- Sell Markets That Show The Greatest Weakness: Metaphorically, when bearish we need to throw rocks into the wettest paper sacks, for they break most easily. When bullish we need to sail the strongest winds, for they carry the farthest.

8. Think Like A Fundamentalist- Trade Like A Simple Technician: The fundamentals may drive a market and we need to understand them, but if the chart is not bullish, why be bullish? Be bullish when the technicals and fundamentals, as you understand, them run in tandem.

9. Trading Runs in Cycles- Some Good- Most Bad: Trade large and aggressively when trading well- trade small and ever smaller when trading poorly. In &#8220-good times,&#8221- even errors turn to profits- in &#8220-bad times,&#8221- the most well researched trade will go awry. This is the nature of trading- accept it and move on.

10. Keep Your Technical Systems Simple: Complicated systems breed confusion- simplicity breeds elegance. The great traders we&#8217-ve known have the simplest methods of trading. There is a correlation here!

11: In Trading/Investing, An Understanding Of Mass Psychology is Often More Important Than An Understanding of Economics: Simply put, &#8220-When they are cryin&#8217-, you should be buyin&#8217-! and when they are yellin&#8217-, you should be sellin&#8217-!&#8221-

12. Bear Market Corrections Are More Violent And Far Swifter Than Bull Market Corrections: Why they are is still a mystery to us, but they are- we accept it as fact and we move on.

13. There Is Never Just One Cockroach: The lesson of bad news on most stocks is that more shall follow&#8230- usually hard upon and always with detrimental effect upon price, until such time as panic prevails and the weakest hands finally exit their positions.

14. Be Patient With Winning Trades- Be Enormously Impatient with Losing Trades: The older we get, the more small losses we take each year&#8230-and our profits grow accordingly.

15. Do More Of That Which Is Working and Less Of That Which Is Not: This works in life as well as trading. Do the things that have been proven of merit. Add to winning trades- Cut back, or eliminate losing ones. If there is a &#8220-secret&#8221- to trading (and of life), this is it.

16. All Rules Are Meant To Be Broken.&#8230- but only very, very infrequently. Genius comes in knowing how truly infrequently one can do so and still prosper.

Prediction Markets Definitions

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We should try to be more careful about our distinctions and definitions. I&#8217-m less concerned about whether we use the phrase &#8220-prediction market,&#8221- &#8220-information market,&#8221- &#8220-decision market,&#8221- or whatever- I&#8217-m more concerned about what exactly these phrases are intended to mean. Here are some possible concepts to distinguish (I&#8217-ll avoid naming them).

  1. Markets that make predictions – Pretty much every speculative market ever created does this.
  2. Markets that make easily interpreted predictions – Most betting markets would be included here, while most financial markets would not. For financial markets one must understand and estimate risk premia, discount factors, and so on be able to say much what exactly the current price estimates.
  3. Markets whose prices embody information – Also pretty much every speculative market ever made.
  4. Markets whose price predictions are used as info by non-traders – Many financial markets meet this criteria.
  5. Markets whose interpretable predictions are used as info by non-traders – Many betting markets meet this criteria.
  6. Markets whose primary function is not hedging – A &#8220-primary&#8221- function would most explain the existence of the market and its volume of activity. Most financial markets might fit here, as most volume is from speculation.
  7. Markets where the main trader motivation is not material gain – Most play money markets would fit this criteria.
  8. Markets where the social value of allowing the market to exist outweighs the social cost – this would be the sort of market we want to legally allow to exist.
  9. Markets where the social value of the info gained by non-traders, but not the social value of its use for hedging, outweighs any other social costs of allowing the market to exist – These markets could justify a legal regime empowered to allow markets to exist for info reasons, not just hedging reasons.
  10. Markets whose primary function is to inform non-traders – Non-trader interest in the info would be the main explanation for the existence of the market and the volume of trade- such non-traders would somehow subsidize the existence of the market and trading activity in order to gain the info they desire.

These last two concepts are of the most interest to me – I would like to have names that clearly identify them and distinguish them from the other concepts.

Overcoming Bias dot com = Robin Hanson’s group blog on truth discovery and decision rationality

A Web-based “forum”, rather, he says:

To me “forum” connotes that we [CFM: the blogging scholars] are primarily talking to each other, though we don’t mind if others join in to comment or listen.

Blog” to me connotes that we are primarily writing for other people, and we are just sharing the load of putting together something for those readers.

URL: Overcoming Bias dot com

Overcoming Bias

Addendum: Robin Hanson has just posted a comment…

Chris, the picture is a famous painting of Ulysses bound to the mast listening to the Sirens; the rest of the crew has their ears plugged to avoid the severely biased Siren Song. 

What Is The Meaning Of His Blog Header? No idea. I wonder whether his 2005 Marginal Revolution post (”Hanged For Accuracy”) gives us a clue:

I came across an even more dramatic example of such thinking in Dava Sobel’s Longitude (1995:11-12):

Returning home victorious from Gibraltar after skirmishes with the French … the English fleet … discovered to their horror that they had misgauged their longitude … the Scillies became the unmarked tombstones for two thousand of Sir Clowdisley’s troops. [Admiral Sir Clowdisley] had been approached by a sailor, … who claimed to have kept his own reckoning of the fleet’s location during the whole cloudy passage. Such subversive navigation by an inferior was forbidden in the Royal Navy, as the unnamed seaman well knew. However, the danger appeared so enormous, by his calculations, that he risked his neck to make his concerns known to the officers. Admiral Shovell had the man hanged for mutiny on the spot. … In literally hundreds of instances, a vessel’s ignorance of her longitude led swiftly to her destruction.

Even though shipmates had a strong common interest in knowing their longitude, other social incentives apparently prevented them from sharing their information. As a consultant on the use of prediction markets within organizations, I’ve also noticed that managers are often surprisingly uninterested in the prospect of more accurate forecasts and more informed decisions. Could these phenomena have similar explanations?

About Overcoming Bias:

How can we better believe what is true? While it is of course useful to seek and study relevant information, our minds are full of natural tendencies to bias our beliefs via overconfidence, wishful thinking, and so on. Worse, our minds seem to have a natural tendency to convince us we that are aware of and have adequately corrected for such biases, when we have done no such thing.

Overcoming Bias dot com will be authored by 14 (academic or not) scholars. Among them, 5 usual suspects from the field of prediction markets, including the owner of this microscopic little blog (who would do just anything to get linked to by Midas Oracle).

Speaking of bias, is our good doctor Robin Hanson as innocent as Snow White? Let’s take a look at “The Wisdom Of His Crowd“. Here’s an excerpt of the 2005 poll he asked his acquaintances (the author of these lines being one among many) to fill in, so as to discover what could be his next academic project.

Here are the ten main choices as I see them now:

1. Disagreement Book – Expand “Are Disagreements Honest” and related papers into a book, adding new material on data about who is right in real disagreements. I’ve been telling people this is my plan. This could establish my reputation as a deep thinker on a big issue. Fun, as there are still things for me to learn on this topic. No real competition on this topic (as least re the more technical angle), and it is nicely not aligned with an ideology. But not clear this will really change much in the world.

See the key sentence??? “I’VE BEEN TELLING PEOPLE THIS IS MY PLAN.” Ha. ha. ha. Totally biased poll. And, SURPRISE, SURPRISE, of course, that poll gave the option #1 (”the disagreement book”) as the most popular answer. NO WONDER. And so we are here, today, with our Robin Hanson opening a group blog on “overcoming bias”. (The “idea futures book” came as a close #2. Had he suppressed the bias in his poll, we would have had Robin Hanson opening a group blog on prediction markets, today, instead.)

Maybe the first topic of discussion among these 14 luminaries (or so they think they are) should be: How to overcome Robin Hanson’s biased polls?

How To Subscribe To Robin Hanson’s Group Blog:

His Royal Highness publicizes the “RSS 1.0″ site feed, on his right sidebar. It’s an old format; complete crap.

Summary of the Tradesports DEMS.HOUSE.OVER29.5 issue, and the TS credibility gap

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In the past weeks, there was something of a dust-up over TS&#8217- handling of the DEMS.HOUSE.OVER29.5 contract. According to all American media, the Democrats needed 15 new House seats to gain control of the House of Representatives. And, indeed, in the final days leading up to the election, there an excellent synchronization between the DEMS.HOUSE.OVER14.5 contract and the inverse of HOUSE.GOP.2006, indicating a perceived equivalence between 100 – p(HOUSE.GOP.2006) and DEMS.HOUSE.OVER14.5. Thus, the (presumably overwhelmingly American) market inferred that TS would follow the same convention as all American media, mainstream and otherwise, did. And according to American media, a Democrat replacing independent Socialist Bernie Sanders didn&#8217-t count as a Democratic pickup, because he already caucused with the Democrats anyway. However, TS initially disagreed with that, and counted Sanders as a non-Democrat. (More on that soon.)

Speaking personally, TS reinforced this perception&#8211-that independents who caucused with the Democrats counted as Democratic seats, and if they were replaced by an official Democrat, that wouldn&#8217-t increase the Democrats&#8217- vote total&#8211-by specifically stating, in regards to SENATE.GOP.2006, that a &#8220-loss&#8221- of the Connecticut seat to Joe Lieberman (who had switched from Democrat to Independent) would still be counted as a Democratic seat, because Lieberman already caucused with the Democrats anyway.

The fine print of the Tradesports DEMS.HOUSE.OVERXX contracts was, for most of the time, fairly clear in stating that the Democrats started from 201 seats, and anything over that number would constitute a gain. Judging from the activity of DEMS.HOUSE.OVER14.5, however, I believe that most of the market inferred (as did I) that 201 was the initial starting number of of Democrat seats according to American convention as well as TS, and didn&#8217-t realize the difference between the two systems. A very technical mistake, but not one for which TS deserved blame.

However, TS threw a monkey wrench in the system by telling forummer &#8220-gekko6&#8243- that Bernie Sanders&#8217- Independent seat going Democratic would not count as a Democratic pickup, because Sanders had already caucused with the Democrats in the first place. In this decision, as in its Connecticut Senate decision, TS showed an impressive grasp of the vagaries of the American political system&#8211-namely, that the size of each caucus was the real issue- and Congressional majorities being determined on the basis of caucus, not party affiliation, it only made sense to calculate the shift in power in the House on the same basis.

Unfortunately, that also meant that TS had, at the same time, repudiated its own convention for what constituted a &#8220-gain.&#8221- &#8220-gekko6&#8243- had already been very aware of this issue, because he had pointed out that the actual starting count according to the American system was 203, not 201&#8211-due to Sanders&#8217- being an independent endorsed and unopposed by the Democrats, and the vacancy of Bob Menendez&#8217-s seat after Menendez was appointed to the Senate by NJ Gov. Corzine. (From a foreign, technical perspective, this was defensible&#8211-Menendez&#8217-s seat was vacant, so the winner on Nov. 7 would count it as a &#8220-gain.&#8221- However, the Republicans did not contest Menendez&#8217-s very Democratic seat, so in the American convention, it was never counted as a Democratic pickup.) Tradesports&#8217- convention effectively said that the Democrats gained two more seats than the American convention did, and several days after the November elections, the American convention said that the Democrats had gained 28 House seats with 1 certain to go Democratic in a runoff (in Louisiana), so 29 seats total, while the Democrats had effectively gained 31 seats according to TS. Hence the problem with DEMS.HOUSE.OVER29.5. And while a legalistic interpretation would favor TS, I believe that the synchronization of DEMS.HOUSE.OVER14.5 and 100 – p(HOUSE.GOP.2006) indicated that most trading during the final few days showed that the market was unaware of TS&#8217- own convention for the election outcome.

I sent Tradesports an e-mail about it (apparently they don&#8217-t accept new entrants to their forum anymore, because my application has been pending for about a month), and they replied that the new number of Democrats minus 201 would constitute the number of Democrat gains, thus contradicting what they had told &#8220-gekko6.&#8221- I then publicly denounced TS for waffling the issue. TS did nothing, and apparently hoped the controversy would blow over. A bunch of recounts in close races later, TS appears to have lucked out, because according to the American convention, the Democrats now have at least 233 House members, up from 202-plus-one-Socialist, so the American system now says the Democrats have gained 30 seats and DEMS.HOUSE.OVER29.5 has been fulfilled either way.

Honestly, I was impressed that TS understood the American system as well as they did. Unfortunately, TS&#8217- subsequent &#8220-flip-flopping&#8221- showed that it did not, in fact, understand its own contract specifics. It also fit a larger pattern of cavalier disdain for its clients, often interpreting an ambiguous outcome significantly contrary to that of the market-majority (Harriet Miers confirmation, NK missile test contract) without appropriate compensation, setting up a joke &#8220-Arbitration Committee&#8221- that, if it even exists, has done nothing except infuriate customers, and most recently expiring sports contracts before the games were even concluded &#8211-and coincidentally raking in tons of expiry fees from people who weren&#8217-t given a chance to liquidate.

The latter, in fact, has happened with enough cavalier consistency that one can only wonder whether TS simply plans on milking its American consumers for as much as possible before closing the site to new American participants as a result of the recent US legislation. SportsBook has downgraded Tradesports to a C+ rating, which is at the very low end of what SportsBook can vouch for.

If TS plans on more effectively structuring its futures contracts, it should structure them along the lines of, &#8220-At 11:59:59 PM GMT on dd/mm/yyyy, Democrats will control ON or OVER XXX seats in the US House of Representatives.&#8221- If it wants to undertake a broader effort to restore its own credibility, it needs to stop the caprice that is fast becoming the norm for how it adjudicates contract outcomes&#8211-whether that adjudication occurs before or after the outcome has actually occurred. [added:] TS&#8217- infrastructure and trader base are both excellent, and there&#8217-s no point in wasting those assets on sloppy legalese and interpretation.

&#8211-Alex Forshaw

http://the-ts-maven.blogspot.com

Tradesports forum homepage: http://forum.tradesports.com/

Addendum: As for 100 – p (HOUSE.GOP.2006) vs DEMS.HOUSE.OVER14.5, I remember them consistently mirroring one another, and thinking to myself, &#8220-Aha! Efficient markets at work.&#8221- However, what little historical data TS makes publicly available makes it hard to judge that, and there were snapshots when the two were de-coupled, so perhaps a minority of perceptive traders _did_ trade on the differences in the rules. But in the sample of snapshots that I looked at, the two were coupled (within 2 points) much more often than not during the final days, when liquidity was high enough to make arbitraging the two contracts a worthwhile use of capital.

PEAR lab (Princeton Engineering Anomalies Research) – REDUX – Retrocausality in physics

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In my previous blog post, I said that Princeton professor Robert Jahn has been unable of finding the right hypothesis about the so-called &#8220-psychic phenomena&#8221- (if any). I mentioned the work of a theoretical physicist, Olivier Costa de Beauregard, who interprets the E.P.R. paradox using the concept of &#8220-retrocausality&#8221- (the reversal of the arrow of time). I said that, speaking of the so-called &#8220-psychic ability&#8221- (if any), one could interpret the so-called &#8220-precognition&#8221- (if any) as a reversal of the psychological arrow of time, where the mind could receive information coming from its own future.

Well, today, via Jason Kottke, we have some news from the scientific world that scratches this concept of &#8220-retrocausality&#8221- (which we should not confuse with &#8220-finality&#8221-, I was told), and which seems to comfort the Costa de Beauregard&#8217-s interpretation:

Quantum theory describes the behavior of matter and energy at the atomic and subatomic levels, a level of reality where most of the more familiar Newtonian laws of physics (why planets spin, airplanes fly and baseballs curve) no longer apply. The problem with quantum theory, put simply, is that it&#8217-s really weird. Findings at the quantum level don&#8217-t fit well with either Newton&#8217-s or Einstein&#8217-s view of reality at the macro level, and attempts to explain quantum behavior often appear inherently contradictory. &#8220-There&#8217-s a whole zoo of quantum paradoxes out there,&#8221- Cramer said. &#8220-That&#8217-s part of the reason Einstein hated quantum mechanics.&#8221- One of the paradoxes of interest to Cramer is known as &#8220-entanglement.&#8221- It&#8217-s also known as the Einstein-Podolsky-Rosen paradox, named for the three scientists who described its apparent absurdity as an argument against quantum theory. Basically, the idea is that interacting, or entangled, subatomic particles such as two photons &#8212- the fundamental units of light &#8212- can affect each other no matter how far apart in time or space. &#8220-If you do a measurement on one, it has an immediate effect on the other even if they are separated by light years across the universe,&#8221- Cramer said. If one of the entangled photon&#8217-s trajectory tilts up, the other one, no matter how distant, will tilt down to compensate. Einstein ridiculed the idea as &#8220-spooky action at a distance.&#8221- Quantum mechanics must be wrong, the father of relativity contended, because that behavior requires some kind of &#8220-signal&#8221- passing between the two particles at a speed faster than light.

This is where going backward in time comes in. If the entanglement happens (and the experimental evidence, at this point, says it does), Cramer contends it implies retrocausality. Instead of cause and effect, the effect comes before the cause. The simplest, least paradoxical explanation for that, he says, is that some kind of signal or communication occurs between the two photons in reverse time. It&#8217-s all incredibly counterintuitive, Cramer acknowledged. But standard theoretical attempts to deal with entanglement have become a bit tortured, he said. As evidence supporting quantum theory has grown, theorists have tried to reconcile the paradox of entanglement by basically explaining away the possibility of the two particles somehow communicating. &#8220-The general conclusion has been that there isn&#8217-t really any signaling between the two locations,&#8221- he said. But Cramer said there is reason to question the common wisdom. Cramer&#8217-s approach to explaining entanglement is based on the proposition that particles at the quantum level can interact using signals that go both forward and backward in time. It has not been the most widely accepted idea. But new findings, especially a recent &#8220-entangled photon&#8221- experiment at the University of Innsbruck, Austria, testing conservation of momentum in photons, has provided Cramer with what he believes is reason for challenging what had been an untestable, standard assumption of quantum mechanics.

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Parting Shot: If &#8220-psychological retrocausality&#8221- (&#8220-precognition&#8221-, actually) could be engineered one day, then we could make a killing on prediction markets. I could have sold short the SENATE.GOP.2006 contract at TradeSports, and made as much money as scientist David Pennock did (or so he claims &#8212-and I saw that some vendor also made this self-interested and undocumented claim).

TradeSports-InTrade: United Nations > John Bolton as US Ambassador to United Nations – REDUX

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I&#8217-ve spotted an interesting comment from Canadian trader Sacha Peter on the TradeSports forum:

This will be an interesting contract. Essentially, will Bush recess appoint him? I can&#8217-t see him getting past the senate confirmation process.

I lost a few bucks (literally, it wasn&#8217-t huge) in the previous confirmation debacle, so the way they worded this contract is very unambiguous and Tradesports appears to have learned one lesson.

So here&#8217-s the contract statement:

This contract will expire at 100 if John Bolton is the US Ambassador to the United Nations at 11:59:59pm on the date specified in the contract.

This includes (but is not limited to) confirmation by the US Senate or a recess appointment by the President.

The contract will expire at 0 if John Bolton is not the US Ambassador to the United Nations at 11:59:59pm on the date specified in the contract.

This includes (but is not limited to) withdrawal of the nomination by the President, withdrawal by John Bolton himself, failure to be confirmed by the US Senate or appoinment to an &#8220-acting UN Ambassador&#8221- role under the Vancacies Reform Act.

Due to the nature of this contract please also see Contract Rule 1.9 Unforeseen Circumstances.

The Exchange reserves the right to invoke Contract Rule 1.8 (Time Protection) if deemed appropriate.

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This entry is a follow-up on my previous blog post.

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Price for John Bolton as US Ambassador to United Nations at TradeSports.com

Does Liquidity Affect Securities Market Efficiency? – Paul Tetlocks new abstract

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Does Liquidity Affect Securities Market Efficiency? – (PDF – Listed at CFM) – [previous title: Does Noise Trading Affect Securities Market Efficiency?] – by Paul Tetlock – 2006-11-XX

The basic idea of the paper is simple. I measure liquidity and expected returns for various securities, and show that the two are linked. In an efficient market, the benchmark is that all securities should have zero expected returns. I find that the illiquid securities markets have (close to) zero expected returns, implying that these markets are efficient. But the liquid securities show certain mispricing patterns. The nature of these patterns suggests that individuals&#8217- probability misperceptions are the cause of the mispricing in liquid securities.

Note: the zero expected returns benchmark is a simplification. It&#8217-s based on the assumption that the equilibrium price of risk is negligible, which is a good approximation for most securities on TradeSports &#8211-e.g., sports contracts, and most of the short-term financial contracts. Obviously, this assumption would fail in conventional financial markets, where risk premiums may be large.

Previous Blog Posts:

Paul Tetlock on the inner working of TradeSports-InTrade

– No change: Mispricing is greater in illiquid markets + Justin Wolfers&#8217-s comment

– Does Liquidity Affect Securities Market Efficiency?

Short Odds for Ignorance

Gambling and a New Approach to Regulating Information Markets

External Link:

– TradeSports forum thread

Parting Shot:

Yeah, it was the Paul Tetlock festival, today.

Ouch! – Finding from a Web usability expert (Jakob Nielsen): 50% of Web readers dont scroll down the webpage.

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From today&#8217-s New York Times:

Studies by Mr. Nielsen’s company, the Nielsen Norman Group, an Internet design firm in Fremont, Calif., show that only 50 percent of Web visitors scroll down the screen to see what lies below the visible part on their PC monitor. “Users spend 30 seconds reviewing a home page,” Mr. Nielsen said. “A business must encapsulate what they do in very few words.”

Web Usability Links:

– Jakob Nielsen: UseIt.com – AlertBox –

– David Pennock and Robin Hanson, the wannabe bloggers, would probably pass the following Jakob Nielsen test: Weblog Usability: The Top Ten Design Mistakes – by Jakob Nielsen – 2005-10-17

– Alex Kirtland – Blog: Usable Markets – E-mail interview with Alex Kirtland.

Prediction Markets vs. Political Pundits – 2006 US Senate (GOP control + individual races)

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&#8230- More exactly TradeSports-InTrade and Iowa Electronic Markets VERSUS The McLaughlin Group (PBS).

Reason Magazine writes:

Weirdly, the McLaughlin Group, the fustiest of all the talking head shows, had one of the best records this cycle, with Eleanor Clift, Lawrence O&#8217-Donnell, and John McLaughlin all predicting Democratic takeover of the Senate and calling nearly all of the close races correctly. Still, that old line about stopped clocks comes to mind.

Reality Check:

Vo, vo, vo. Not so fast. The McLaughlin Group is made up of five members. Three of them predicted the Dems in the US Senate, and so (if I&#8217-m correct) the associated probability was 3/5 = 60%. It does not strike me as an unanimous consensus.

As for TradeSports, Professor Lance Fortnow wrote that all (NOT: &#8220-nearly all&#8221-) individual 2006 US Senate races were predicted correctly.

More Links:

– The McLaughlin Group (PBS + CNBC Europe)

– 2006-11-03: Transcript – Audio (MP3) – Video (MP4) –

Parting Shot:

If the small-L and capital-L libertarians at Reason Magazine sides with the leftist bloggers and media in the anti-PM backlash, and if some from-day-one prediction market supporter goes amock, then the logical conclusion is: The Prediction Markets Have NOT Arrived Yet.