Archive for The New York Times

running shoes

Posted in Books, Running, Statistics with tags , , , , , , , , , , on August 12, 2018 by xi'an

A few days ago, when back from my morning run, I spotted a NYT article on Nike shoes that are supposed to bring on average a 4% gain in speed. Meaning for instance a 3 to 4 minute gain in a half-marathon.

“Using public race reports and shoe records from Strava, a fitness app that calls itself the social network for athletes, The Times found that runners in Vaporflys ran 3 to 4 percent faster than similar runners wearing other shoes, and more than 1 percent faster than the next-fastest racing shoe.”

What is interesting in this NYT article is that the two journalists who wrote it have analysed their own data, taken from Strava. Using a statistical model or models (linear regression? non-linear regression? neural net?) to predict the impact of the shoe make, against “all” other factors contributing to the overall time or position or percentage gain or yet something else. In most analyses produced in the NYT article, the 4% gain is reproduced (with a 2% gain for female shoe switcher and a 7% gain for slow runners).

“Of course, these observations do not constitute a randomized control trial. Runners choose to wear Vaporflys; they are not randomly assigned them. One statistical approach that seeks to address this uses something called propensity scores, which attempt to control for the likelihood that someone wears the shoes in the first place. We tried this, too. Our estimates didn’t change.”

The statistical analysis (or analyses) seems rather thorough, from what is reported in the NYT article, with several attempts at controlling for confounders. Still, the data itself is observational, even if providing a lot of variables to run the analyses, as it only covers runners using Strava (from 5% in Tokyo to 25% in London!) and indicating the type of shoes they wear during the race. There is also the issue that the shoes are quite expensive, at $250 a pair, especially if the effect wears out after 100 miles (this was not tested in the study), as I would hesitate to use them unless the race conditions look optimal (and they never do!). There is certainly a new shoes effect on top of that, between the real impact of a better response and a placebo effect. As shown by a similar effect of many other shoe makes. Hence, a moderating impact on the NYT conclusion that these Nike Vaporflys (flies?!) are an “outlier”. But nonetheless a fairly elaborate and careful statistical study that could potentially make it to a top journal like Annals of Applied Statistics!

and it only gets worse…

Posted in Kids, pictures with tags , , , , , , , , , , , , , , , , , , , , , , , on July 23, 2018 by xi'an

“David Brooks, the New York Times columnist, recently summed up the “Trumpian world-view” writing, “Trump takes every relationship that has historically been based on affection, loyalty, trust and reciprocity and turned it into a relationship based on competition, self-interest, suspicion and efforts to establish dominance.” NYT, June 14

“Donald Trump has dismissed concerns about the widely condemned human rights record of the North Korean dictator, Kim Jong-un, praising him as a “tough guy”, a “smart guy” and a “great negotiator”.” The Guardian, June 14

“Clinics that call themselves crisis pregnancy centers are not obliged to tell women when state aid may be available to obtain an abortion, according to a US supreme court ruling that represents a blow to pro-choice groups (…) All three of the court’s female members dissented.” The Guardian, June 27

“A resolution to encourage breast-feeding was expected to be approved quickly and easily by the (…) United Nations-affiliated World Health Assembly. Based on decades of research, the resolution says that mother’s milk is healthiest for children and countries should strive to limit the inaccurate or misleading marketing of breast milk substitutes. Then the United States delegation, embracing the interests of infant formula manufacturers, upended the deliberations. The intensity of the administration’s opposition to the breast-feeding resolution stunned public health officials and foreign diplomats, who described it as a marked contrast to the Obama administration.” NYT, July 8

“President Trump on Tuesday pardoned a pair of Oregon cattle ranchers who had been serving out sentences for arson on federal land (…) The pardons undo an Obama administration appeal to impose longer sentences for the Hammonds and show that, at least in this case, the Trump administration is siding with ranchers in the battle over federal lands.” NYT, July 10

“President Trump stood next to President Vladimir V. Putin of Russia on Monday and publicly challenged the conclusion of his own intelligence (…) “No prior president has ever abased himself more abjectly before a tyrant,” Senator John McCain, Republican of Arizona, said in a statement. “Today’s press conference in Helsinki was one of the most disgraceful performances by an American president in memory.” ” NYT, July 16

“The Interior Department on Thursday proposed the most sweeping set of changes in decades to the Endangered Species Act, the law that brought the bald eagle and the Yellowstone grizzly bear back from the edge of extinction but which Republicans say is cumbersome and restricts economic development.” NYT, July 20

and it only gets worse…

Posted in Kids, pictures with tags , , , , , , , , , , , , , , , , , on June 3, 2018 by xi'an

“Donald Trump’s attacks on the press are “out of control” and damaging “the civic life and debate of the country”, the editor of the New York Times said on Sunday. Dean Baquet was responding to a tweet in which the president attacked his main rival. “The Washington Post is far more fiction than fact,” Trump wrote. `Story after story is made up garbage – more like a poorly written novel than good reporting. Always quoting sources (not names), many of which don’t exist.’ ” The Guardian, April 8

The Trump administration is expected to announce today a rule that would strip federal funding from clinics that provide abortions or refer patients to places that do. The rule, a return to a Reagan-era policy, is a victory for social conservatives. It’s also a jab at Planned Parenthood, which serves 41 percent of women who receive federally funded family planning services.2  NYT, May 18

“Donald Trump pulled the US out of the landmark nuclear deal with Tehran on Tuesday, moving to re-impose sanctions on Iran and defying pleas from close allies who had called for the agreement to be preserved. The decision marks a bitter defeat for America’s European allies, who have spent months beseeching Mr Trump to stay in a deal that he has denounced as “insane”. Critics warned it would further endanger stability in the Middle East. ” FT, May 8

“Donald Trump has slammed the gun laws of major US allies, claiming foreign countries could better protect their citizens – and possibly stop terrorist attacks – by loosening their gun control laws. In a speech to the NRA Leadership Forum, Mr Trump sought to reassure members of the US’s largest gun rights lobbying group of his support for the Second Amendment, after briefly expressing support for gun control measures in the wake of a school shooting in Florida.” The Independent, May 5


Les Enfants Rouges

Posted in Kids, pictures, Travel with tags , , , , , , , on February 4, 2018 by xi'an

An happenstance reservation at Les Enfants Rouges led to a great and unique meal. The restaurant is located in Le Marais, north of Paris City Hall, and the chef Daï Shinozuka brings a precision in the cooking and presentation of traditional French food that makes each dish a masterpiece. Above the “neo bistro-fare” lauded by The New York Times. But definitely part of the new and exciting food scene in Paris!


algorithm for predicting when kids are in danger [guest post]

Posted in Books, Kids, Statistics with tags , , , , , , , , , , , , , , , , , on January 23, 2018 by xi'an

[Last week, I read this article in The New York Times about child abuse prediction software and approached Kristian Lum, of HRDAG, for her opinion on the approach, possibly for a guest post which she kindly and quickly provided!]

A week or so ago, an article about the use of statistical models to predict child abuse was published in the New York Times. The article recounts a heart-breaking story of two young boys who died in a fire due to parental neglect. Despite the fact that social services had received “numerous calls” to report the family, human screeners had not regarded the reports as meeting the criteria to warrant a full investigation. Offered as a solution to imperfect and potentially biased human screeners is the use of computer models that compile data from a variety of sources (jails, alcohol and drug treatment centers, etc.) to output a predicted risk score. The implication here is that had the human screeners had access to such technology, the software might issued a warning that the case was high risk and, based on this warning, the screener might have sent out investigators to intervene, thus saving the children.

These types of models bring up all sorts of interesting questions regarding fairness, equity, transparency, and accountability (which, by the way, are an exciting area of statistical research that I hope some readers here will take up!). For example, most risk assessment models that I have seen are just logistic regressions of [characteristics] on [indicator of undesirable outcome]. In this case, the outcome is likely an indicator of whether child abuse had been determined to take place in the home or not. This raises the issue of whether past determinations of abuse– which make up  the training data that is used to make the risk assessment tool–  are objective, or whether they encode systemic bias against certain groups that will be passed through the tool to result in systematically biased predictions. To quote the article, “All of the data on which the algorithm is based is biased. Black children are, relatively speaking, over-surveilled in our systems, and white children are under-surveilled.” And one need not look further than the same news outlet to find cases in which there have been egregiously unfair determinations of abuse, which disproportionately impact poor and minority communities.  Child abuse isn’t my immediate area of expertise, and so I can’t responsibly comment on whether these types of cases are prevalent enough that the bias they introduce will swamp the utility of the tool.

At the end of the day, we obviously want to prevent all instances of child abuse, and this tool seems to get a lot of things right in terms of transparency and responsible use. And according to the original article, it (at least on the surface) seems to be effective at more efficiently allocating scarce resources to investigate reports of child abuse. As these types of models become used more and more for a wider variety of prediction types, we need to be cognizant that (to quote my brilliant colleague, Josh Norkin) we don’t “lose sight of the fact that because this system is so broken all we are doing is finding new ways to sort our country’s poorest citizens. What we should be finding are new ways to lift people out of poverty.”

and it only gets worse…

Posted in Kids, pictures with tags , , , , , , , , , , , , , , , , , , , , on December 2, 2017 by xi'an

“You know, the saddest thing is that because I’m the president of the United States, I am not supposed to be involved with the Justice Department,” Mr. Trump said in a radio interview on Thursday on the “Larry O’Connor Show.” “I am not supposed to be involved with the F.B.I. I’m not supposed to be doing the kind of things that I would love to be doing. And I’m very frustrated by it.” NYT, Nov 03, 2017

“Two former US intelligence chiefs have said Donald Trump poses “a peril” to the US because he is vulnerable to being “played” by Russia, after the president said on Saturday he believed Vladimir Putin’s denials of Russian interference in the 2016 election.” The Guardian, Nov 12, 2017

“As a result [of the 44% of vacant seats in the appeal courts], Mr. Trump is poised to bring the conservative legal movement, which took shape in the 1980s in reaction to decades of liberal rulings on issues like the rights of criminal suspects and of women who want abortions, to a new peak of influence over American law and society.” NYT, Nov 11, 2017

“Hunting interests have scored a major victory with the Trump administration’s decision to allow Americans to bring home body parts of elephants shot for sport in Africa. Another totemic species now looks set to follow suit – lions.”  The Guardian, Nov 16, 2017

“Like everything else Trump touches, he hijacks it with his chronic dishonesty and childishness,” said Mark Salter, a longtime adviser to Senator John McCain, Republican of Arizona. “The intense, angry and largely ignorant tribalism afflicting our politics predates Trump’s arrival on the scene. But he has infused it with a psychopath’s inability to accept that social norms apply to him.” NYT, November  18, 2017

“We represent a much larger number of concerned mental health professionals who have come forward to warn against the president’s psychological instability and the dangers it poses. We now number in the thousands.” NYT, November 31, 2017

long journey to reproducible results [or not]

Posted in Books, pictures, Statistics, University life with tags , , , , , , , , , on November 17, 2017 by xi'an

A rather fascinating article in Nature of last August [hidden under a pile of newspapers at home!]. By Gordon J. Lithgow, Monica Driscoll and Patrick Phillips. About their endeavours to explain for divergent outcomes in the replications [or lack thereof] of an earlier experiment on anti-aging drugs tested on roundworms. Rather than dismissing the failures or blaming the other teams, the above researchers engaged for four years (!) into the titanic and grubby task of understanding the reason(s) for such discrepancies.

Finding that once most causes for discrepancies (like gentle versus rough lab technicians!) were eliminated, there were still two “types” of worms, those short-lived and those long-lived, for reasons yet unclear. “We need to repeat more experiments than we realized” is a welcome conclusion to this dedicated endeavour, worth repeating in different circles. And apparently missing in the NYT coverage by Susan Dominus of the story of Amy Cuddy, a psychologist at the origin of the “power pose” theory that got later disputed for lack of reproducibility. Article which main ideological theme is that Cuddy got singled-out in the replication crisis because she is a woman and because her “power pose” theory is towards empowering women and minorities. Rather than because she keeps delivering the same message, mostly outside academia, despite the lack of evidence and statistical backup. (Dominus’ criticisms of psychologists with “an unusual interest in statistics” and of Andrew’s repeated comments on the methodological flaws of the 2010 paper that started all are thus particularly unfair. A Slate article published after the NYT coverage presents an alternative analysis of this affair. Andrew also posted on Dominus paper, with a subsequent humongous trail of comments!)