Lunch at the Labs

Various web links I found to be of interest recently:

• Randomness, Skill, and Investment Strategies

  Campbell Harvey of Duke University talks with EconTalk podcast host Russ Roberts about his research evaluating various investment and trading strategies and the challenge of measuring their effectiveness.

  Among topics discussed, two examples of (mis)understanding randomness given:
  • Significant: Jelly Beans Cause Acne
    
  • So let me set up what actually happens. So, let's say after those 10 weeks in a row you actually subscribe to this person's predictions. And then they don't do so well, after the 10 weeks. And the reason is that the original strategy was basically: Send an email to 100,000 people, and in 50,000 of those emails you say that Team A is going to win on Monday. And in 50,000 you say Team B is going to win on Monday. And then, if Team A wins, the next week you only send to the people that got the correct prediction. So, the next week you do the same thing. 25,000 for Team A, 25,000 for Team B. And you continue doing this. And the size of the number of emails decreases every single week, until after that 10th week, there are 97 people that got 10 picks in a row correct. So you harvest 97 suckers out of this.

• No autism-vaccine link, study finds

  Research should focus on prenatal causes of the disorder, scientists say

  No association was found between autism and getting the MMR vaccine, according to a study published Tuesday in JAMA.
  The study of 95,000 children with older siblings also examined those at high risk for autism spectrum disorder (ASD), namely those who have an older autistic sibling. No link between the measles, mumps and rubella vaccine and autism was found in these high-risk children, researchers said in the study.

• Declining Desire to Work and Downward Trends in Unemployment and Participation

  The US labor market has witnessed two apparently unrelated trends in the last 30 years: a decline in unemployment between the early 1980s and the early 2000s, and a decline in labor force participation since the early 2000s. We show that a substantial factor behind both trends is a decline in desire to work among individuals outside the labor force, with a particularly strong decline during the second half of the 90s. A decline in desire to work lowers both the unemployment rate and the participation rate, because a nonparticipant who wants to work has a high probability to join the unemployment pool in the future, while a nonparticipant who does not want to work has a low probability to ever enter the labor force. We use cross-sectional variation to estimate a model of nonparticipants' propensity to want a job, and we find that changes in the provision of welfare and social insurance, possibly linked to the mid-90s welfare reforms, explain about 50 percent of the decline in desire to work.

• The Placebo Gene?

  In the current study researchers performed a retrospective analysis of an existing study population in which there was a no-treatment arm (waitlist control), placebo acupuncture with minimal practitioner interaction, and placebo acupuncture with enhanced emotional support (the "warm and fuzzy" arm). The study population are those with IBS, a syndrome known to have a substantial emotional component. Further, the outcome was the subjective report of symptoms from the subjects. In other words - the syndrome and outcomes were amenable to maximal placebo responses. Prior studies have consistently shown that for subjective symptoms such as this the interaction with the practitioner is the single most important factor in reporting a subjective improvement in symptoms from a placebo intervention.
  ... Patients with the gene variant associated with increased dopamine activity in both alleles (copies of the gene) showed more of a placebo response, especially to the warm and fuzzy intervention. While again I have to emphasize the preliminary nature of this research, the results are plausible and do make sense. IBS is particularly susceptible to suggestion and a warm interaction with a practitioner, interventions that reduce anxiety and improve mood. Anxiety, mood, and the emotional response to pain and discomfort are all brain phenomena, and dopamine is an important brain neurotransmitter involved with emotion and reward, so it's not surprising.
  

• FT Masterclass: Pickpocketing and how to avoid it with James Freedman

  I ask if there are certain hotspots where pickpockets strike. Tourist spots, Freedman tells me, especially places such as Big Ben and the Eiffel Tower, where people's attention is directed upwards and away from their belongings. He says that many pickpockets also operate near signs warning us to beware of pickpockets. The irony is that when people read the signs, they check their pockets or bag, thus alerting the lurking pickpocket to where their valuables are.

• Study: Believing You've Slept Well, Even If You Haven't, Improves Performance

  Results: Participants who were told they had above-average REM sleep performed better on the test, and those who were told their REM sleep was below average performed worse, even when researchers controlled for the subjects' self-reported sleep quality.
  Implications: A great victory was won here for lies, over truth. This study shows that if you're in the mindset that you're well-rested, your brain will perform better, regardless of the actual quality of your sleep. Conversely, constantly talking about how tired you are, as so often happens in our culture, might be detrimental to your performance.

• Can you succeed at anything with enough practice?

  How much is achievement based on natural ability and how much hard work?

  In an international experiment, a table-tennis coach gave an "unsporty" adult an hour's coaching every day for a year in a bid to make him one of the top table tennis players in Britain.
  Why did the project fail?
  Table tennis has the smallest court, the smallest ball, the smallest bat, the quickest reaction times, the most spin, and it's the only sport where you play on one surface but stand on another.

• Why I am a Climate Change Skeptic

  Dr. Patrick Moore, Greenpeace co-founder and former director Greenpeace International.

  My skepticism begins with the believers' certainty they can predict the global climate with a computer model. The entire basis for the doomsday climate change scenario is the hypothesis increased atmospheric carbon dioxide due to fossil fuel emissions will heat the Earth to unlivable temperatures.
  ... In fact, the Earth has been warming very gradually for 300 years, since the Little Ice Age ended, long before heavy use of fossil fuels. Prior to the Little Ice Age, during the Medieval Warm Period, Vikings colonized Greenland and Newfoundland, when it was warmer there than today. And during Roman times, it was warmer, long before fossil fuels revolutionized civilization.
  The idea it would be catastrophic if carbon dioxide were to increase and average global temperature were to rise a few degrees is preposterous.

• It's Not The Heat, It's the Tepidity

  Clifford Asness and Aaron Brown

  Of course the real but rather small trend doesn't prove that global warming is a minor issue, far from it. We're just saying the graph taken on its own is actually pretty reassuring, at least compared to predictions, and declared danger points, of the IPCC and similar groups. If things continue along the way they have for the last 135 years, the point at which we reach dangerous temperatures is a very very long time from now. Those predicting that we face a big problem much sooner aren't arguing this from these data, instead they have to be arguing that historical warming trends will change drastically in the near future; that they will not continue at the trend of the past hundred years or so. The historical record to date, and in particular this ubiquitous graph, can't be the basis of an argument that we will hit dangerous levels soon . To argue that we will hit them in this, or even next century requires us to explain away this graph, to explain why the rate of warming will increase.
  ... Of course, this raises the very important issue of whether or not 4°C is the right danger line. No one knows the answer to this question, but 4°C seems the most common figure used by the experts. It’s what the IPCC uses in its most recent report. No one denies that there are some risks and costs to any amount of warming, and on the other hand, almost no one is predicting that warming at or slightly beyond 4°C will cause extinction of the human race either. Risks go up with the amount of warming. We just don't know how fast. Despite the uncertainties, there seems to e a scientific consensus that less than 1°C or 2°C of warming would make global warming no more serious than several other environmental issues, but warming above 4°C would likely make global warming a unique danger. Even if the danger point is 2°C this trend doesn't reach it until over 130 years from now.

  For reactions and rebuttals see Imagine if They Disagreed With Us!

  What we did not expect was the immediate and strong chorus of agreement, yes agreement, from climate scientists. Equally unexpected was that their agreement would be couched in unfriendly terms!