5 Easy Pieces

/ bs king

Simply Statistics put up this link to an interview with David Spiegelhalter on 5 good books to help understand statistics and risk.  I haven’t read any of them, but they looked excellent.  Also, this quote is excellent:

There is a nice quote from Joel Best that “all statistics are social products, the results of people’s efforts”. He says you should always ask, “Why was this statistic created?” Certainly statistics are constructed from things that people have chosen to measure and define, and the numbers that come out of those studies often take on a life of their own.

I’m pretty sure that about sums it up.

Skin cancer, sunscreen, and connecting the dots

/ bs king / 2 Comments

There is skin cancer in my family.  My grandfather has had it, and occasionally a doctor will try to tell me that I am genetically predisposed to it because of this.  While I try to practice good sun habits, I am dubious about the “genetic predisposition” argument.  You see, my grandfather spent several years in the early 40’s hanging out in the sun in the Phillipines while monitoring Japanese aircraft activity.  He thinks that’s more responsible for his skin cancer than genes.  I do too.

Regardless, you might say, it’s a good idea to wear sunscreen right?  Of course.  Except it may not help.

As it turns out, sunscreen formulas that prevent sunburn may not be equally good at preventing cancer.  And you may not be putting enough on.  And they may have chemicals in them that actually increase your cancer risk rather than decrease it.  Huh.

I’ve talked before about making sure you connect all the dots, not just proving disjointed ideas.  We know that sunscreen prevents sunburn, and people who get sunburns are more likely to get skin cancer.  The troubling part is that there is no proof that people who wear sunscreen get less skin cancer.  It’s tempting to jump from A to C, but you have to remember things can go wonky when you don’t remember the stop at B.

Regardless of the data, sunburns are painful, and I’m still very Irish, so I would recommend sunscreen in general…but lets not oversell the good it might be doing.

Religion and income

/ bs king / 2 Comments
Religion and income distribution.  Not sure I get exactly what data they used to get this, but still kind of interesting.  Incomes seem to skew upward the smaller the group, which makes a certain amount of sense.

 The Hindu numbers surprised me a bit.  I was guessing that has something to do with the high percentage of Indians in tech/healthcare professions, presumably making $100k+.  

Things to ponder on a Sunday

Retractions, while sometimes necessary, are never as good as the real thing

/ bs king / 2 Comments

Since starting this blog, I’ve become quite the fan of the website Retraction Watch.

One of the more interesting ongoing stories has been the number of retractions from Dipak Das, the UCONN researcher who faces massive misconduct charges for fabricating data in his research about the health benefits of red wine.

His current retraction count stands at 13 papers, with 145 counts of misconduct being investigated.

While the role of his work in the field is contested, one can’t debate that his results were widely reported and certainly helped with the public perception that red wine is good for you.  Thus, I found it interesting that Jezebel was running an article at the same time about the further proof that red wine is good for you.  In the background they mention some of the studies that Das did, that have since been retracted.  Not that this is necessarily their fault….recently it was found that only a quarter of retracted articles in online databases carry a retraction notice, and this drops to 5% if you look at downloadable PDFs.

People have complained about this with newspapers for years….large headlines, little tiny retractions…but with the ever increasing retraction rate and the centrality of the internet, this is liable to get worse before it gets better.

Economic Data, and why I don’t talk about it

/ bs king / 1 Comment

I find it really hard to even comment on economic data on this blog.  It’s based on so many assumptions and there are so many different numbers that can be included or excluded that critiquing it is a combination of trying to shoot fish in a barrel and trying to catch a greased pig.

Not my idea of a good time.

Anyway, BD Keller linked to an excellent post today that is way more articulate than I about why evidence based monetary policy is so hard to come by.

On economic experimental models:

Think of a good experimental design: randomised control variables, holding everything else constant, etc. Now think of the worst possible experimental design. Imagine something that engineers or psychologists might dream up over beers for a laugh, or to illustrate what not to do. That’s what economists face. It’s as if our lab assistants (the fiscal and monetary authorities) were deliberately trying to make our (economists’) lives as hard as possible. They do this, of course, not to spite us, but to try to make everyone else’s lives as easy as possible. To get a good experimental design for economists, both the fiscal and monetary authorities would need to be malevolent.

Makes sense, but given this, I do wish they’d stop saying their predictions with such authority.

Does egg = cigarette?

/ bs king / 2 Comments

Oh CNN, your headlines make me sad sometimes.

Is eating egg yolks as bad as smoking?

No.  No it is not.  The study you’re reporting on does in fact claim that eating egg yolks accelerate heart disease about 2/3rds as much as smoking does, but acceleration of heart disease is not actually the health problem smoking is most known for.  But you know that.  Sigh.

Not that I’m buying the study anyway.  They asked people, who already had heart disease, to report their egg yolk consumption over the course of their lives.  How accurately can you recall your average egg yolk consumption over the course of your life?  Additionally, people who have heart disease have most likely been told to cut down on consumption of saturated fat and cholesterol.  Those still eating more eggs have likely heard this advice, and disregarded it.  What are the chances that they’re disregarding other advice as well?  Lastly, it does not appear the study asked about the consumption of any other food, meaning egg consumption could actually just be co-occuring with the consumption of something else that was even worse.  Surveys that ask only about very specific foods tend to see what they want to see.

So basically, another correlation/causation issue here, combined with those terrible consumption recollection surveys, with a sprinkle obnoxious headline writing.   Yeehaw.

Now THAT’s how you write a science headline

/ bs king / 3 Comments

“Babies Shun Altruism, Prefer Bouncing”

Speaking of replication of results, this study failed to substantiate the idea that 10 month old babies had a moral code.  Turns out that the their preference for “helpful” robots was based less on the fact that the robots were helpful, and more on the fact that they bounced.

I’m sort of curious how many of the original study authors were parents.  I’ve only been a mom for 19 days and even I could tell you that babies like bouncy things more than discussions about man’s existential angst.  The 2 AM feeding helps you figure these things out pretty quickly.

For fun, I decided to conduct my own n=1 experiment and to present my son with a survey regarding his preference for robots in general and their morals in particular.  I thought it was a fairly well crafted survey.

I think my findings are best summarized with this picture:

I think that should be good enough for any number of social psychology journals.  

Replication of results

/ bs king / 2 Comments

I haven’t talked much here about reproducing results of studies, mostly because most studies have so much to pick at from the outset that it doesn’t matter.  However, a new initiative is looking to highlight reproducibility in scientific studies, and encourage independent verification of results.

I think this is pretty cool.

Right now, journals tends to value originality of research over anything else, and that can lead to incentive problems.  In fact, the woman who helped start the replication initiative did so after she had trouble finding someone to publish a paper that called in to question her own previous research when she was unable to replicate it.

Repeating results is supposed to be one of the fundamentals of the scientific method.  Good to see it finally getting it’s due.

Year of the Snake (also, Statistics…but not Algebra)

/ bs king / 5 Comments

My credit for links is beginning to go downhill, I blame the baby thing.  When I find good links, I leave the page open in Chrome, but don’t often leave the source open as well.  No one told me having a child would cause my internet etiquette to go so precipitously downhill.

All that to say, I have no idea where I saw this, but apparently 2013 has been declared The International Year of Statistics.  
Sadly, none of the events are in my neck of the woods, but still fun to know about.  
It also brought to mind this NYT Op-Ed piece about the necessity of algebra.  I’m a bit tardy in bringing it up, as there have been quite a few good responses to it already, but I wanted to throw my two cents in.  
Andrew Hacker argues that algebra and other current math standards are impractical and unfairly hold back people who aren’t good at math.  My first reaction was annoyance.  No one would ever argue that someone deserved to graduate high school without being able to read, no matter how much they excelled at math….and yet here someone is essentially arguing the reverse.  
When I took a deep breath however, it occurred to me that the last thing I want to do is defend the way math is taught to most high schoolers.  For many people, a course on functional statistics and/or financial math would be more useful, practical, and most likely easier to learn and remember.  If we’re headed that direction, there’s probably very few subjects taught in high school that couldn’t be improved with a little more practicality and a little less theory. 
To get back to the start of the post, I wouldn’t mind seeing algebra replaced with more statistical teaching….though large scale public understanding of stats and research methods might leave me with fewer things to blog about.  

Olympics of Yesteryear

/ bs king / 6 Comments

Well the Olympics have come and gone, but I’m still not over my crush on the plethora of Olympic related data out there.  Indulge me one last time, as I repost the Economist’s list of discontinued Olympic events.

Who knew tug of war was in there until 1920?  They should bring that back.