Category Archives: Research

Understanding the Karni Belief-Revelation Mechanism

Suppose you wanted to find out someone’s subjective belief in the likelihood of a given event. Your first instinct might be to offer them betting odds on the event. If they would accept odds of 2:1 but no lower, you might conclude that they believe the event to have a 33.3% chance of occurring.

This would be correct if the person you’re offering the bet to is risk neutral. But if they’re risk averse, they might actually believe the event has a 50% likelihood of occurring, and they just require more favourable odds to compensate them for accepting risk.

Luckily, there’s a better way to elicit subjective probabilities. It comes from Karni (2009), a short paper published in Econometrica.* Continue reading Understanding the Karni Belief-Revelation Mechanism

Scotland’s Curious Three-Verdict System

Lately I’ve been interested in true crime stories. It started with Serial and Undisclosed, two excellent podcasts on the case of Adnan Syed, a Baltimore teenager wrongfully (yes, wrongfully) convicted of killing his girlfriend in 1999. Then came the popular Netflix documentary Making a Murderer, which detailed the case of Steven Avery, who was wrongfully convicted of rape in 1985, released in 2003 after being exonerated by DNA evidence, and then (apparently) framed for murder.

Kill the wife, frame the husband. Only an owl could be so dastardly.
Kill the wife, frame the husband. Only an owl could be so dastardly.

Because of my interest in these stories, my parents recommended I watch another, less known documentary series called Death on the Staircase. The series documented the trial of Michael Peterson (no relation) for allegedly killing his wife Kathleen. He found Kathleen at the base of the staircase and assumed she had taken a fall. The prosecution claimed that he actually beat her to death. However, the physical evidence didn’t really match a beating (no skull fractures or brain contusions, no splatter on the ceiling), nor did it match a fall (falls don’t usually cause that amount of bleeding). Neither theory can explain the microscopic owl feathers found in Kathleen’s hand, nor the suspiciously talon-shaped lacerations on her scalp.

In all four of these cases (including both of Steven Avery’s convictions), the jury found the defendant guilty on the basis of flawed, circumstantial evidence. I think all three men are innocent, but even if I’m wrong or have been misled (though I’ve done independent research on all three cases), it seems like there must be at least a reasonable doubt of their guilt. So how could the juries convict them? Unless… Continue reading Scotland’s Curious Three-Verdict System

Predictions for 2016

This year I will be making a series of predictions about the future, and assigning each of them a probability. I was inspired to do so by Scott Alexander and Phillip Tetlock. Too many commentators make vague predictions about future events and then declare victory however things turn out. So, in the interest of holding myself to a higher standard than a fortune cookie or horoscope, here are my predictions for 2016:

World Events

  1. Canadian year-over-year CPI growth will be higher than it was in December 2015: 90%
  2. Canadian year-over-year CPI growth will be at least 2.0%: 60%
  3. American year-over-year CPI growth will stay below 1.0%: 60%
  4. American year-over-year CPI growth will stay below 2.0%: 80%
  5. Unemployment in the US will be lower than it was in December 2015: 60%
  6. Unemployment in Canada will be lower than it was in December 2015: 60%
  7. Canadian year-over-year real GDP growth will be lower in 2016 than in 2015: 70%
  8. American year-over-year real GDP growth will be lower in 2016 than in 2015: 60%
  9. Iranian year-over-year real GDP growth will be higher in 2016 than it was in 2015: 80%
  10. The S&P 500 will end 2016 lower than it started: 60% (note that I am making this prediction on January 26th, and it has already fallen since January 1st)
  11. The price of crude oil will be above $35 USD at the end of 2016: 70%
  12. The price of crude oil will be above $30 USD at the end of 2016: 90%
  13. The price of Bitcoin will be above $400 USD at the end of 2016: 70%
  14. The Canadian Federal Government will not decriminalize marijuana: 90%
  15. The US Federal Government will not decriminalize marijuana: 99%
  16. At least one more US State will decriminalize adult use and cultivation of marijuana: 60%
  17. Donald Trump will not win the Republican nomination: 60%
  18. Conditional on Trump winning the nomination, voter turnout as a percentage of the voting age population will be higher than it was in the 2012 presidential election: 90%
  19. Conditional on Trump losing the nomination, voter turnout as a percentage of the voting age population will be lower than it was in the 2012 presidential election: 60%
  20. Hillary Clinton will be the Democratic nominee: 80%
  21. Hillary Clinton will be elected President: 60%
  22. ISIS will hold less territory than it did at the beginning of 2016: 90%
  23. ISIS will lose Raqqa: 60%
  24. The Force Awakens’ worldwide gross will exceed that of Titanic: 80%
  25. The Force Awakens’ worldwide gross will not exceed that of Avatar: 80%
  26. No 2016 movie will gross more than The Force Awakens: 90%
  27. Leonardo DiCaprio will finally win an Oscar: 90%

Continue reading Predictions for 2016