Interesting discussion from David Gorski (which I found via this link from Joseph Delaney). I don’t have anything really to add to this discussion except to note the value of this sort of anecdote in a statistics discussion. It’s only n=1 and adds almost nothing to the literature on the effectiveness of various treatments, but [...]
Archive of posts filed under the Decision Theory category.
Comparing prediction errors
Someone named James writes:
That advice not to work so hard
We often hear that at the end of life, people often wish they hadn’t worked so hard. (I’m assuming this is coming from executive types who have the option of working less, not people who had to work hard just to put food on the table.) I don’t understand this. Work is ok, but in [...]
Economists don’t think like accountants—but maybe they should
Joseph Delaney quotes Frances Woolley: In other words, the reason we care about inequality is that it reduces the happiness achievable from a given amount of income. How much depends upon the happiness/income relationship. Does the marginal utility of income fall rapidly? Or is the happiness from the 100,000th dollar almost as great as the [...]
n = 2
People in Chicago are nice. The conductor on the train came by and I asked if I could buy a ticket right there. He said yes, $2.50. While I was getting the money he asked if the ticket machine at the station had been broken. I said, I don’t know, I saw the train and [...]
Some thoughts on academic cheating, inspired by Frey, Wegman, Fischer, Hauser, Stapel
As regular readers of this blog are aware, I am fascinated by academic and scientific cheating and the excuses people give for it. Bruno Frey and colleagues published a single article (with only minor variants) in five different major journals, and these articles did not cite each other. And there have been several other cases [...]
What’s “the definition of a professional career”?
Last month I expressed disagreement the following statement from New Republic columnist Jonathan Chait, who wrote: The old liberal slogan always demanded that we “treat teachers like professionals.” That entails some measure of accountability—we can debate the metrics—which allows both that very bad teachers be fired and that very good ones can obtain greater pay [...]
Why it doesn’t make sense in general to form confidence intervals by inverting hypothesis tests
Peter Bergman points me to this discussion from Cyrus of a presentation by Guido Imbens on design of randomized experiments. Cyrus writes: The standard analysis that Imbens proposes includes (1) a Fisher-type permutation test of the sharp null hypothesis–what Imbens referred to as “testing”–along with a (2) Neyman-type point estimate of the sample average treatment [...]
Participate in a research project on combining information for prediction
Thomas Wallsten writes: To viewers of Dr. Andrew Gelman’s blog, I [Wallsten] am pleased to invite you to participate in an important research project to develop improved methods for predicting future events and outcomes. More specifically, our goal is to develop methods for aggregating many individual judgments in a manner that yields more accurate predictions [...]
Is it rational to vote?
Hear me interviewed on the topic here. P.S. The interview was fine but I don’t agree with everything on the linked website. For example, this bit: Global warming is not the first case of a widespread fear based on incomplete knowledge turned out to be false or at least greatly exaggerated. Global warming has many [...]
Another plagiarism mystery
Nick Cox comments: I heard of a leading U.S. statistician who delegates some of his book reviews to smart graduate students. The (very grateful) ex-student who told me said, in effect, it’s just his way of working. He makes the deal evident beforehand and makes it up to you in other ways by superb mentoring. [...]
Grade inflation: why weren’t the instructors all giving all A’s already??
There’s been some discussion lately about grade inflation. Here’s a graph from Stuart Rojstaczer (link from Nathan Yau): Rojstaczer writes: In the 1930s, the average GPA at American colleges and universities was about 2.35, a number that corresponds with data compiled by W. Perry in 1943. By the 1950s, the average GPA was about 2.52. [...]
Don’t idealize “risk aversion”
Richard Thaler writes (click here and search on Thaler): Both risk and risk aversion are concepts that were once well defined, but are now in danger of becoming Aetherized [this is Thaler's term for adding free parameters to a model to make it work, thus destroying the purity and much of the value of the [...]
On the half-Cauchy prior for a global scale parameter
Nick Polson and James Scott write: We generalize the half-Cauchy prior for a global scale parameter to the wider class of hy- pergeometric inverted-beta priors. We derive expressions for posterior moments and marginal densities when these priors are used for a top-level normal variance in a Bayesian hierarchical model. Finally, we prove a result that [...]
How do we evaluate a new and wacky claim?
Around these parts we see a continuing flow of unusual claims supported by some statistical evidence. The claims are varyingly plausible a priori. Some examples (I won’t bother to supply the links; regular readers will remember these examples and newcomers can find them by searching): – Obesity is contagious – People’s names affect where they [...]
New ideas on DIC from Martyn Plummer and Sumio Watanabe
Martyn Plummer replied to my recent blog on DIC with information that was important enough that I thought it deserved its own blog entry. Martyn wrote: DIC has been around for 10 years now and despite being immensely popular with applied statisticians it has generated very little theoretical interest. In fact, the silence has been [...]
How the ignorant idiots win, explained. Maybe.
According to a New York Times article, cognitive scientists Hugo Mercier and Dan Sperber have a new theory about rational argument: humans didn’t develop it in order to learn about the world, we developed it in order to win arguments with other people. “It was a purely social phenomenon. It evolved to help us convince [...]
Hey, good news! Your p-value just passed the 0.05 threshold!
E. J. Wagenmakers writes: Here’s a link for you. The first sentences tell it all: Climate warming since 1995 is now statistically significant, according to Phil Jones, the UK scientist targeted in the “ClimateGate” affair. Last year, he told BBC News that post-1995 warming was not significant–a statement still seen on blogs critical of the [...]
Suspicious pattern of too-strong replications of medical research
Howard Wainer writes in the Statistics Forum: The Chinese scientific literature is rarely read or cited outside of China. But the authors of this work are usually knowledgeable of the non-Chinese literature — at least the A-list journals. And so they too try to replicate the alpha finding. But do they? One would think that [...]
Shocking but not surprising
Much-honored playwright Tony Kushner was set to receive one more honor–a degree from John Jay College–but it was suddenly taken away from him on an 11-1 vote of the trustees of the City University of New York. This was the first rejection of an honorary degree nomination since 1961. The news article focuses on one [...]
Statistics ethics question
A graduate student in public health writes: I have been asked to do the statistical analysis for a medical unit that is delivering a pilot study of a program to [details redacted to prevent identification]. They are using a prospective, nonrandomized, cohort-controlled trial study design. The investigator thinks they can recruit only a small number [...]
“Rationality” reinforces, does not compete with, other models of behavior
John Sides followed up on a discussion of his earlier claim that political independents vote for president in a reasonable way based on economic performance. John’s original post led to the amazing claim by New Republic writer Jonathan Chait that John wouldn’t “even want to be friends with anybody who” voted in this manner. I’ve [...]
The payoff: $650. The odds: 1 in 500,000.
Details here.
Free $5 gift certificate!
I bought something online and got a gift certificate for $5 to use at BustedTees.com. The gift code is TP07zh4q5dc and it expires on 30 Apr. I don’t need a T-shirt so I’ll pass this on to you. I assume it only works once. So the first person who follows up on this gets the [...]
The free cup and the extra dollar: A speculation in philosophy
The following is an essay into a topic I know next to nothing about.
As part of our endless discussion of Dilbert and Charlie Sheen, commenter Fraac linked to a blog by philosopher Edouard Machery, who tells a fascinating story:
How do we think about the intentional nature of actions? And how do people with an impaired mindreading capacity think about it?
Consider the following probes:
The Free-Cup Case
Joe was feeling quite dehydrated, so he stopped by the local smoothie shop to buy the largest sized drink available. Before ordering, the cashier told him that if he bought a Mega-Sized Smoothie he would get it in a special commemorative cup. Joe replied, ‘I don’t care about a commemorative cup, I just want the biggest smoothie you have.’ Sure enough, Joe received the Mega-Sized Smoothie in a commemorative cup. Did Joe intentionally obtain the commemorative cup?
The Extra-Dollar Case
Joe was feeling quite dehydrated, so he stopped by the local smoothie shop to buy the largest sized drink available. Before ordering, the cashier told him that the Mega-Sized Smoothies were now one dollar more than they used to be. Joe replied, ‘I don’t care if I have to pay one dollar more, I just want the biggest smoothie you have.’ Sure enough, Joe received the Mega-Sized Smoothie and paid one dollar more for it. Did Joe intentionally pay one dollar more?
You surely think that paying an extra dollar was intentional, while getting the commemorative cup was not. [Indeed, I do--AG.] So do most people (Machery, 2008).
But Tiziana Zalla and I [Machery] have found that if you had Asperger Syndrome, a mild form of autism, your judgments would be very different: You would judge that paying an extra-dollar was not intentional, just like getting the commemorative cup.
I’m not particularly interested in the Asperger’s angle (except for the linguistic oddity that most people call it Asperger’s but in the medical world it’s called Asperger; compare, for example, the headline of the linked blog to its text), but I am fascinated by the above experiment. Even after reading the description, it seems to me perfectly natural to think of the free cup as unintentional and the extra dollar as intentional. But I also agree with the implicit point that, in a deeper sense, the choice to pay the extra dollar isn’t really more intentional than the choice to take the cup. It just feels that way.
To engage in a bit of introspective reasoning (as is traditional in in the “heuristics and biases” field), I’d say the free cup just happened whereas in the second scenario Joe had to decide to pay the dollar.
But that’s not really it. The passive/active division correctly demarcates the free cup and extra dollar examples, but Machery presents other examples where both scenarios are passive, or where both scenarios are active, and you can get perceived intentionality or lack of intentionality in either case. (Just as we learned from classical decision theory and the First Law of Robotics, to not decide is itself a decision.)
Machery’s explanation (which I don’t buy)