Delegate at Large

Delegate at Large Posted by Andrew on 29 July 2017, 9:42 am Asher Meir points to this delightful garden of forking paths, which begins: • Politicians on the right look more beautiful in Europe, the U.S. and Australia.• As beautiful people earn more, they are more likely to oppose redistribution.• Voters use beauty as a cue for conservatism in low-information elections.• Politicians on the right benefit more from beauty in low-information elections. I wrote: On the plus side, it did not appear in a political science journal! Economists and psychologists can be such suckers for the “voters are idiots” models of politics. Meir replied: Perhaps since I am no longer an academic these things don’t even raise my hackles anymore. I just enjoy the entertainment value. This stuff still raises my hackles, partly because I’m in the information biz so I…
Original Post: Delegate at Large

Died in the Wool

Garrett M. writes: I’m an analyst at an investment management firm. I read your blog daily to improve my understanding of statistics, as it’s central to the work I do. I had two (hopefully straightforward) questions related to time series analysis that I was hoping I could get your thoughts on: First, much of the work I do involves “backtesting” investment strategies, where I simulate the performance of an investment portfolio using historical data on returns. The primary summary statistics I generate from this sort of analysis are mean return (both arithmetic and geometric) and standard deviation (called “volatility” in my industry). Basically the idea is to select strategies that are likely to generate high returns given the amount of volatility they experience. However, historical market data are very noisy, with stock portfolios generating an average monthly return of around…
Original Post: Died in the Wool

How does a Nobel-prize-winning economist become a victim of bog-standard selection bias?

Someone who wishes to remain anonymous writes in with a story: Linking to a new paper by Jorge Luis García, James J. Heckman, and Anna L. Ziff, an economist Sue Dynarski makes this “joke” on facebook—or maybe it’s not a joke: How does one adjust standard errors to account for the fact that N of papers on an experiment > N of participants in the experiment? Clicking through, the paper uses data from the “Abecedarian” (ABC) childhood intervention program of the 1970s. Well, the related ABC & “CARE” experiments, pooled together. From Table 3 on page 7, the ABC experiment has 58 treatment and 56 control students, while ABC has 17 treatment and 23 control. If you type “abecedarian” into Google Scholar, sure enough, you get 9,160 results! OK, but maybe some of those just have citations or references to…
Original Post: How does a Nobel-prize-winning economist become a victim of bog-standard selection bias?

NIMBYs and economic theories: Sorry / Not Sorry

This post is not by Andrew. This post is by Phil. A few days ago I posted What’s the deal with the YIMBYs?  In the rest of this post, I assume you have read that one. I plan to post a follow-up in a month or two when I have had time to learn more, but there are a couple of things I can say right now. I. Sorry I apologize unreservedly to YIMBY supporters who know, or think they know, that buiding more housing in San Francisco will decrease rents there or at least will greatly reduce the rate at which they rise. I characterized the entire YIMBY movement as being at least partly motivated by a desire to stick a thumb in the eye of the smug slam-the-door-now-that-I’m-inside NIMBY crowd, rather than by a genuine belief that loosening…
Original Post: NIMBYs and economic theories: Sorry / Not Sorry

Higher credence for the masses: From a Ted talk?

The Four Most Dangerous Words? A New Study Shows | Laura Arnold | TEDxPennsylvaniaAvenue I brought this link forward in some comments but wanted to promote it to a post as I think its important and I know many folks just do not read comments.As I once heard claimed in a talk on risk communication – “No one has as much credibility as a mother voicing concerns about her children – No one!” Now, academics have been voicing concerns about the quality of published studies and claims for a long time, me in 1989, others inspired by Fisher in 1959 and CS Peirce in 1879. Recently there has been an exponential explosion in the voicing of concerns about  the quality of published studies – but it does not seem to be reaching the masses. Academics must not have much credibility with…
Original Post: Higher credence for the masses: From a Ted talk?

What’s the deal with the YIMBYs?

This post is not by Andrew. It is by Phil. There’s at least one thing people in San Francisco seem to agree on: the rent is too damn high. The median rent is between about $3000 and $3500 per month…for a one-bedroom apartment. High-tech workers and upper-echelon businesspeople can afford a place, but baristas and hair salon workers and teachers and shop clerks etc. etc. have real trouble. Of course there is plenty of development pressure, and new high-rise apartments are going in that have hundreds of apartments each, typically with a rent of $4000 – $8000 per month. If you let a developer build “market rate” apartments, that’s what they’ll build. Suppose San Francisco adds 10,000 market-rate units. Some will be one-bedrooms, some two- or three-bedrooms, and some will be occupied by singles, others by couples, etc. But for…
Original Post: What’s the deal with the YIMBYs?

Reality meets the DeLilloverse

Reality meets the DeLilloverse Posted by Andrew on 11 May 2017, 6:23 pm From 2009: “They thought ASU’s brand was too strong to compete with. Incarnate Word is now part of the Communiversity @ Surprise, a newly opened one-stop learning center for higher education in the northwest Valley.” I guess my statistics textbooks probably read like parodies of statistics textbooks, so from that perspective it makes sense that the above business-speak reads like a parody of business-speak. It’s the combination of biz-jargon “Communiversity @ Surprise” with the biblical “Incarnate Word” that takes this one into DeLillo territory.
Original Post: Reality meets the DeLilloverse

Can you account for this?

I’m speaking (remotely) to a roomful of accountants tomorrow. Exciting, huh? Actually, I don’t know if they’re accountants. They’re “accounting researchers,” whatever that means. . . . The title they gave to my talk is “A statistician’s thoughts on registered reports.” There’s no abstract (and, of course, no slides) but they sent me this list of relevant issues: 1. Power is essential for any good empirical research. How effective is registration at improving power? The positive, given they way we are doing it, is that people can commit to gathering a lot of high-quality data, knowing that they will be published regardless of whether they support their results. 2. How helpful is it really to reduce HARKing [hypothesizing after results are known]? 3. How effective is registration in reducing p-hacking, especially given that so many of the interesting results in…
Original Post: Can you account for this?

“Everybody Lies” by Seth Stephens-Davidowitz

Seth Stephens-Davidowitz sent me his new book on learning from data. As is just about always the case for this sort of book, I’m a natural reviewer but I’m not really the intended audience. That’s why I gave Dan Ariely’s book to Juli Simon Thomas to review; I thought her perspective would be more relevant than mine for the potential reader. I took the new book by Stephens-Davidowitz and passed it along to someone else, a demanding reader who I thought might like it, and he did: he kept coming to me with new thought-provoking bits that he’d found in it. So that’s a pretty solid endorsement. I couldn’t convince him to write a review so you’ll have to take my word that he liked it. The thing I found most appealing about the book was that, in addition to…
Original Post: “Everybody Lies” by Seth Stephens-Davidowitz