The curious case of the cyclist’s unshaven legs
theglobeandmail.com
theglobeandmail.com
This drive for unending novelty in the sciences is a shame on many levels. The good and useful work of duplicating and verifying results goes undone, and scientists are driven ever more forcefully towards designing studies only on the basis of what will attract grant agencies.
Duplicating major results carefully would be useful to the scientific record. Trying things that will probably fail, and then publishing negative results, would be useful too. But, for most researchers, doing this useful work appears to be career suicide.
That nobody spent $500-$2000 to estimate leg hair drag probably speaks more about people not wanting to be caught measuring leg hair drag than about the entire field's tendency to replicate findings. It's also really weird for people to consider $500/hour tunnel time to be expensive for a sport with as much money as cycling.
Really, I thought it was weird, and probably inappropriate, to mix in so much of an outsider's amateur and unsopported opinion about science into an otherwise interesting story about leg hair drag.
If there's a serious story somewhere about results not getting replicated when they should in many fields of science, I'd like to hear about it. There's often stuff on the fringe, but any serious result will be replicated soon. Take, for example, the acid-bath stem cell retraction from not long ago. Where else are important results not replicated? The Higgs? It's a baffling perspective.
Everything We Know Is Wrong http://www.bbc.co.uk/programmes/b04f9r4k
Actually, there is! It's been referred to as "the decline effect", and it's fascinating.
The New Yorker published an article about it a few years ago (http://www.newyorker.com/magazine/2010/12/13/the-truth-wears...). It has resurfaced in popularity a couple of times. It was written by disgraced journalist Jonah Lehrer, but later independent investigation failed to find any fault with the article he wrote (http://www.lastwordonnothing.com/2012/11/05/jonah-lehrer-nat... -- worth reading because it includes statements from scientists on Lehrer's article).
So far, my favorite explanation is the direct, obvious one, which is that we're sometimes -- perhaps more often than we'd expect -- falling victim to statistics. Given the very large number of experiments and studies being conducted everywhere, and the selection for positive results, statistical anomalies are being accidentally selected for and then not being extensively enough re-evaluated much later.
The article discusses that as a possible explanation, but the journalist does his job, igniting reader interest, by suggesting the effect somehow "defies the laws of statistics". I favor the simpler explanation, which is that our meat brains simply underestimate the vast number of ways in which statistics would like to bugger us.
Some of the things that both you and the parent commenter mention are discussed in the article. For example:
> Jennions, similarly, argues that the decline effect is largely a product of publication bias, or the tendency of scientists and scientific journals to prefer positive data over null results, which is what happens when no effect is found.
and
> Richard Palmer, a biologist at the University of Alberta, who has studied the problems surrounding fluctuating asymmetry, suspects that an equally significant issue is the selective reporting of results—the data that scientists choose to document in the first place.
(aside: I'm not one of HN's vocal "science is junk" members. I love science, or, at least, I like to admire its butt (http://explosm.net/comics/3557/). I don't believe there's something fundamentally wrong with the scientific method. But, I do think more emphasis needs to be placed on repeatability of experimental results over longer periods of time, and I hope that this will become more of a trend as the world economy continues to grow.)
However, it's all examples of things being replicated in the sense of (1) being tested again, and being "not replicated" in the sense of (2) being tested again and being found to not repeat as initial reports.
I think the article's complaint was about (1), though I find this (2) far more interesting and will pursue these threads, thanks!
I once heard a natural language processing professor observe that a typical NLP conference might have twenty presenters, each giving results to a 95% confidence. "So even if everyone does all their work flawlessly, every conference will have on average one set of bad results."
Journal referees will set the bar for such findings very very high...and you are quite likely to be refereed by the original author or their friends.
I know this to my cost having gone to extraordinary lengths to publish something slightly contradictory in a far lower impact journal than the work deserved.
Those same scientists are motivated to protect their own existing and future work. The academic standards you are subjected to will be far higher than work supporting the status quo.
All of which goes to say that pre-print publication is the way to gooooo.
That's a lot of money to most of them, especially when they can be testing fit and position which have well known advantages to both aero and power output AND they already shave.
This does not represent the experience of many millions of scientists.
You should consider that all science is on the fringe - the purpose of academic science is to research novel ideas.
1. The original study may be plain wrong. Author 1 claims to describe phenomena X, author 2 can't find any evidence for X using the exact same methodology.
2. The original study is wrong because the methodology is bad, interpretation is incorrect, reagents are not specific, techniques are not clean, etc.
There's a strong argument to be made that it is more important to do orthogonal work which indirectly verifies the original results, as opposed to simply trying to reproduce the original work. This solves both #1 and #2.
The paper cited in the article is a great example. Gluing hair onto a plastic leg and putting it in a miniature wind tunnel is probably an exercise in bad methodology—but they might have still gotten the right result for their experiment. And that's useful because now we know that there may be something different about either plastic legs vs. real legs or miniature wind tunnels vs. big wind tunnels. This is a trite example, but it should be clear how this might be more important in other studies.
"Ioannidis's 2005 paper "Why Most Published Research Findings Are False"[5] has been the most downloaded technical paper from the journal PLoS Medicine.[8] A profile of his work in this area appears in the November 2010 issue of The Atlantic.[9] The Atlantic article notes Ioannidis analyzed "49 of the most highly regarded research findings in medicine over the previous 13 years". In the paper Ioannidis compared the 45 studies that claimed to have uncovered effective interventions with data from subsequent studies with larger sample sizes: 7 (16%) of the studies were contradicted, 7 (16%) the effects were smaller than in the initial study and 31 (68%) of the studies remained either unchallenged or the findings could not be replicated.[5]
Statisticians Goodman and Greenland agreed that "many medical research findings are less definitive than readers suspect" but disputed his headline claims as unsupportable by the methods used.[10][11] Ioannidis responded to this critique[12] and other researchers have generally supported the general thrust of his findings.[13][14] Ioannidis' work is focused on improving research design standards."
Some rich person needs to start a program incentivizing this kind of work.
I agree about publishing negative results. The experiments that don't work, but might have had a high impact will likely be repeated, as no one knows it hasn't been tried.
If only science publishers would agree. But they're in a money-making business and novel results, "breakthrough" results, even if unverified and soon to be disproven, sell journals much more efficiently than null results or falsifications of earlier work.
If you are interested in this, then the book Faster: The Obsession, Science and Luck Behind the World's Fastest Cyclists by Michael Hutchinson is really good (and very well written).
He notes that human intuition about aerodynamics just isn't very good (you have to test) and that the current state of the art is no longer wind tunnel testing but computational fluid dynamics (CFD) followed by testing with a power meter on the road.
CFD lets designers iterate much quicker on designs and try things outside the norm (avoiding the local maxima problem). Power meters plus riding is better than wind tunnel testing because things like variable cross winds are very hard to test in wind tunnels.
[1] https://www.youtube.com/watch?v=DZnrE17Jg3I
[2] http://www.amazon.com/Faster-Obsession-Science-Fastest-Cycli...
Faster talks about a certain dimpled TT helmet[1], and how it would probably work really well if your head rotated continuously while you rode.
[1] The book doesn't name which one, but this is the only dimpled TT helmet I know of: http://www.louisgarneau.com/in-en/product/826916/1405156/Vie...
That is why this study was so surprising. They found that hair decreased drag.
Shaving reduces the drag, but the originally study measured the reduction around 0.6 percent while this one found a 7 percent reduction. So, about 10 times bigger than anticipated.
When I read this "Even more confounding was that the results contradicted earlier findings" it totally colored my reading of the article. (Emphasis mine.)
Bicycling manufacturers always skew the numbers for how much savings (time, watts, whatever) their new top of the line frames will give you. It's all smoke and mirrors.
This isn't true. Watch the video - he's pedaling when they test.
There's some much more turbulence from just moving your legs, that shaved or not shaved makes almost 0 difference.
That's almost exactly wrong. It's true that pedalling creates turbulence, but the speed your legs move and the turbulence created by that movement is almost entirely disguised by other effects.
For example, the fact a bike is asymmetrical (because of the drivetrain) is a much bigger factor than turbulence because of moving legs.
It is important that testing includes pedaling, because there can be particular positions that work better on some bikes (or for some people) than others.
But in this case the testing used sensible protocols and the difference is a real thing.
Bicycling manufacturers always skew the numbers for how much savings (time, watts, whatever) their new top of the line frames will give you. It's all smoke and mirrors.
That may be the case, but all Specialized is selling here is their aerodynamic expertise (at least until you can buy a Specialized razor blade).
Specialized has something to sell - their business practices, especially with their trademark protection, has been ridiculous, which has been a turn off to people who think clearly.
The market for high-end bikes are people who can afford the bikes, which is usually not the people who would see any difference in buying the $2k bike, rather than the $15k bike. Specialized really doesn't want you to understand this, so they make wildly exaggerated claims about their equipment. People who benefit from fractions of a percent better performance usually are people who are sponsored by the bike company (and thus, get the bikes for free). A difference of a few seconds, over a 50km course makes sense for the elite time trialist, in the Pro tour, it makes 0 difference to your weekend warrior, doing an hour long crit.
Who the heck am I? I'm someone that rides bikes, often for very long distances, to break records (which I do). Don't believe the hype, unless you don't especially have an interesting in holding onto your money.
I'll concede only that my views are unpopular, but that certainly doesn't mean they're incorrect.
But in this case it is unlikely their findings are particularly biased. It's worth noting that the point of the original article was that the Specialized testing actually verified an earlier finding that hadn't been tested properly since.
Yes they are. Chris Yu (running Specialized's wind tunnel; the only bicycle company with their own) is a CalTech/Stanford trained aerodynamicist and competitive cyclist. Give him some credit.
[1] http://www.slowtwitch.com/Downloads/TK10_SC_white_paper_lore...
[2] http://www.slowtwitch.com/images/trek/TK13_SC_Whitepaper_fin...
We shave because it helps reduce road rash when you go down on asphalt (slide easier) & easier to keep the wounds clean afterwards.
A bit of it is also in-group/out-group signaling.
"Reduce drag" is always the jokey reason I'd use for non-cyclists :)
New test: "The tests showed that shaving his legs reduced Thomas’s drag by about 7 per cent"
Yet the blurb says: ''Even more confounding was that the results contradicted earlier finding''. What's contradictory about those results? Be it 0.6% or 7%, shaving your legs clearly reduces drag.
He pushed the edges of conventional design, and participated in the human powered vehicle races quite a bit.
That's fantastic; I never thought I would hear about him on here.
But maybe I don't fully understand the experimental setup. I'm basing my comments on what I see in https://www.youtube.com/watch?v=DZnrE17Jg3I
And, of course, there are also the benefits of less drag and psychological placebo effect.
I found that combination to lower my times by about 1 second per 50m, or about 5%. I don't know how much of that is attributable to the shaving, but I will say it helped me "feel" way faster.
http://www.reuters.com/article/2012/03/28/us-science-cancer-...
Summary: a team at Amgen discovers 47 of 53 "landmark" studies published in high-quality journals could not be reproduced. A team at Bayer did an internal review of programs they had initiated based on journal studies and found that less than a quarter of those findings could be reproduced.
Three very damning quotes: "Some authors [of the journal articles] required the Amgen scientists sign a confidentiality agreement barring them from disclosing data at odds with the original findings."
"'We went through the paper line by line, figure by figure,' said Begley. 'I explained that we re-did their experiment 50 times and never got their result. He said they'd done it six times and got this result once, but put it in the paper because it made the best story. It's very disillusioning.'"
"The problem goes beyond cancer. On Tuesday, a committee of the National Academy of Sciences heard testimony that the number of scientific papers that had to be retracted increased more than tenfold over the last decade; the number of journal articles published rose only 44 percent."
Academics are pressured to produce publications, not to produce science, and their studies are not always rigorous (not blinded to experimenters, etc.). People with high integrity and ability do produce good science that gets published, but unfortunately that appears to be the minority, even in highly prestigious journals.
So I'm curious: how would you fix it?
One thing the article mentions that might improve things is every journal dedicating one complete issue a year to reproducing the most influential studies of the year. Another could be getting a consortium of pharmas (who try to reproduce studies all the time, because if you're going to successfully make drugs you need the thing to work) to publish their internal data for the benefit of all. Does something like that exist?
Strictly my own imagination, but I'm anticipating the introduction down the road of the world's most advanced hair removal system that gives cyclists a big aerodynamic advantage proven by scientific tests. Yes buy the XYZ system and fly to victory! Wow, I really am jaded, but too many times we've seen it happen.
So much bad science obscures the good work because the latter doesn't make the news, it's far too boring to attract attention. It's the small incremental, tedious, repetitious, careful, persistent work that provides the real advances. Edison I think said, "we find 20,000 ways it doesn't work" and learn something every time we try.
I propose a simple set of remedies. Journals should give highest priority to publishing careful replications of prior studies, whether it's yes/no/maybe. Negative studies whether original or replications are give as much priority and those confirmatory. Novel associations are of course welcome if meeting standards of adequate power to discern something beyond quirky results.
Ultimately, the impact of hyperbolic claims about the meaning of research causes the greatest distortions of scientific process and progress. Journal editors can solve the great bulk of misinformation their journals promulgate. It's remarkably simple. All they have to do is issue an edict, all that authors can write about are the history, background, what they did and factual results of their work. These "rules" apply to observational and experimental work all the same. IOW it would be forbidden to draw conclusions about the what the outcomes mean, what is proven, or what "causes" what.
Sure giving context about past results is necessary and usefully informative, but conclusions are for we the readers to determine. If this was the case, suddenly the strident "answers" and premature incorporation of findings into practice will be sharply reduced. Hysteria will subside. We can then actually use our scientific talent to accomplish honest goals, and solve the real and daunting problems we actually have.
Perhaps this seems a radical view and maybe it is. It's not whether I'm right or anybody will make any of these substantial changes. It is about getting back to careful thoughtful scientific inquiry and reducing misdirected human energies.
I wouldn't have figured it to be so much but this doesn't seem so incredible to me.
Similar thing for swimming.
I always thought it was an urban myth that it made you go faster, and that the real reason was that road rash was easier to treat.
While not the most pleasant process, it avoids stubble and the delayed regrowth means the new hair is sufficiently long to begin providing warmth just in time for when cooler Fall temps arrive. I always considered that to be the real reason why the pros do it with road rash being of secondary concern. Those with shorter leg hair just went along and copied their hairier peers.
The problem I see however is that after being shaved the participant would feel faster and thus behave faster. A sort of placebo effect if you will. At the same time, the cyclist-cultural effect of being 'unshaved' in the first test would make them feel sluggish. The same effect as seen in experiments where participants are presented with negative messages vs positive messages and asked to perform tasks. The participants exposed to negative messages, as expected, perform poorly in comparison to the other group.
In conclusion, I feel, that this 'research' can only be used as something to base you hypothesis on, but it is in no way conclusive in its current setup. You'd need to have random groups of cyclists, some of whom are, to begin with, shaved, and some who are not. It would maybe be easier not to use cyclists in order to find a diverse enough set of participants. Then again I don't know how many regular cyclists go around unshaven.
[1] If you design a study you can actually start from the other end: If you can estimate the size of the effect to be measured, you can calculate the number of people needed for significance beforehand.
(Edited to describe my experience, per "let's not read the article" comment).