The Daily Parker

Politics, Weather, Photography, and the Dog

Statistical sins: smoking v. e-cigratettes

Deeply Trivial finds evidence for why there is little evidence about the safety of e-cigarettes:

[T]he statistical sin here isn't really something the researchers have done (or didn't do). It's an impossibility created by confounds. How does one recruit people who have only smoked e-cigarettes or who at least have very little experience with regular cigarettes? What's happening here is really an issue of contamination - a threat to validity that occurs when the treatment of one group works its way into another group. Specifically, it's a threat to internal validity - the degree to which our study can show that our independent variable causes our dependent variable. In smoking research, internal validity is already lowered, because we can't randomly assign our independent variable. We can't assign certain people to smoke; that would be unethical. Years and years of correlational research into smoking has provided enough evidence that we now say "smoking causes cancer." But technically, we would need randomized controlled trials to say that definitively. 

That's not to say I don't believe there is a causal link between smoking and negative health outcomes like cancer. But that the low level of internal validity has provided fuel for people with an agenda to push (i.e., people who have ties to the tobacco industry or who otherwise financially benefit from smoking). Are we going to see the same debate play out regarding e-cigarettes? Will we have to wait just as long for enough evidence to accrue before we can say something definitive about e-cigarettes?

For my part, their safety or lack of to the smoker makes little difference to me. I just don't like people blowing their exhaust fumes into my environment.

Conventional wisdom vs. evidence

Nate Silver has compared pundit analyses of poll data to actual voting results and determined that the pundits get things consistently wrong and in the wrong direction:

This French election was part of a pattern that I began to notice two years ago in elections in the U.S. and elsewhere in the world. Take the 2012 U.S. presidential election as an example. Most of the mainstream media concluded that the race was too close to call, despite a modest but fairly robust Electoral College lead for then-President Barack Obama. But on Election Day, it was Obama who beat his polls and not Mitt Romney.2

Forecasters are overconfident more often than they might realize — and there’s a lot to be said for media outlets erring on the side of caution until a vote has taken place. But France was the wrong hill for anything-can-happen-because-Trump! punditry to die upon. Whereas Clinton led Trump by just 3 to 4 percentage points in national polls (and by less than that in the average swing state), and “Remain” led “Leave” by only a point or so, Le Pen had consistently trailed Macron by 20 to 25 points.

Despite their vastly different polling, however, Trump, Brexit and Le Pen had all been given a 10 to 20 percent chance by betting markets — a good proxy for the conventional wisdom — on the eve of their respective elections. Experts and bettors were irrationally confident about a Clinton victory and a “Remain” victory — and irrationally worried about a Macron loss. In each case, the polls erred in the opposite direction of what the markets expected.

Pollsters have a difficult and essential job, but they’re under a lot of pressure from media outlets that don’t understand all that much about polling or statistics and who often judge the polls’ performance incorrectly.5 They’re also under scrutiny from voters, pundits and political parties looking for reassurance about their preferred candidates. Social media can encourage conformity and groupthink and reinforce everyone’s prior beliefs, leading them to believe there’s a surfeit of evidence for a flimsy conclusion. Under these conditions, it’s easy for polls to be contaminated by the conventional wisdom instead of being a check on elites’ views — and to be the worse for it.

Can't wait to see the polls on the 2018 U.S. elections.

Things I'll be reading this afternoon

Some articles:

And now, Parker needs a walk.

2016 in numbers

Welcome to another of my annual traditions: the stats dump.

In 2016:

  • Traveling was way, way down over previous years. I only visited one foreign country (the UK) and took only 15 flights all year. That amounted to only 42,588 km, not enough to re-qualify for Platinum status for the first time since 2008.
  • The Daily Parker had only 459 posts, down from 2015's 493, and the lowest since 2010. I was really, really busy this year. Posting suffered.
  • Parker got 211 hours of walks, up 62 from 2015. So he did not suffer as much as the blog.
  • Speaking of walks, I got 4,693,427 steps in 2016, beating 2015 by 29,266 steps—or 0.062%. That puts my 2016 daily average at 12,823.5, compared with 2015's 12,786.7. So, really, 37 steps a day. I think I can do better in 2017; we'll see. I still have yet to crack 50,000 steps in a day. Roll on spring.
  • I'm still not reading as much as I used to. I started 23 books in 2016 (up from 2015's 21) but finished 15. If you're keeping count, yes, I dropped some books I started, and still have a book from 2015 to finish. Again, I hope to do better in 2017.

So here we go. Another year. This one could kill us all. Certainly we're all going to be a lot poorer. But maybe I'll read more books, take more steps, and walk Parker more hours.

(See 2015 and 2014 for comparison.)

Fun with statistics

Multiple news outlets reported today on preliminary Census Bureau numbers for the last year showing Chicago lost more population than any other city in the U.S.:

Census Bureau figures released today show the five collar counties gaining 5,084 residents, not enough to offset the 10,488 decline in Cook County during the period. The population of DuPage and Lake counties decreased slightly. That left Cook County with 5.2 million residents and the six-county region with 8.4 million.

Let's make fun of that, shall we? Chicago lost a little more than 0.2% of its population, which is like my high school losing two people. Or New York losing 30,000. In other words, it's a pretty small number, and it follows 8 years of growth.

Also, given the exponents involved, the 10,488-person decline in population doesn't even move the needle on the total number when expressed in millions. Yes, it left Cook County with 5.2 million residents, but the county started with 5.2 million residents, so...yeah.

Now if we'd lost 50,000, I'd want a news story about that. But I think I might already know.

Statistics: 2015

Here are some numbers illustrating 2015 (cf. 2014 also):

  • I took only 14 trips and flew only 25 segments, visiting 7 states and 4 countries*.
  • Of those, 11 flight segments took off or landed outside the US, which is the highest proportion of international-to-domestic flights in any single year. Those years in which I've flown more international segments were also heavy-travel years in general. For example, in 2001, my heaviest travel year ever, I flew 15 international segments—my record—out of 63 total—also my record.
  • I flew 67,187 km, barely re-qualifying (with bonus points) for American Airlines elite status.
  • The Daily Parker had 493 posts, the lowest since 2010. The daily mean dropped to 1.35, continuing a slight downward trend since 2013.
  • Chargeable hours no longer made any difference as I no longer work as a consultant. However, I did log 148.82 hours walking Parker, 10 more than in 2014.
  • Reading suffered a bit. I started 21 books but only finished 15. On the other hand, I went to more operas in 2015 than any year previously, and also ate at more Michelin-starred restaurants than in the preceding 45 years combined.
  • 2015 was the first full year for which I have complete Fitbit statistics. During the year, I walked 4.67 million steps, averaging 12,787 per day; slept 2,287 hours, averaging 6.3 per night; and had a net loss of 1.2 kg. (Though at one point in 2015 I had lost 4.1 kg, and am now hoping that the slight bump in November and December was simply holiday food.)

In 2016, I expect more travel, more Daily Parker posts, about the same number of books, and the same number of live performances.

* Germany, Poland, the UK, and Italy; DC, Virginia, New York, Wisconsin, Indiana, Arizona, California, and Texas.