Wednesday, November 15, 2017

SearchResearch Challenge (11/15/17): What causes such crazy cone and flower production?

There is a tide in the affairs of men,
Which, taken at the flood, leads on to fortune;
Omitted, all the voyage of their life
Is bound in shallows and in miseries.
On such a full sea are we now afloat…


This is from Shakespeare's Julius Caesar, at the moment when Brutus is encouraging Caesar to act because the time is right, and there's no better time likely to come soon.  

There's an equivalent moment in the life of plants that's equally propitious... Or is it?  

I've noticed something as I wander around, looking at plants and trees:  Sometimes the pine trees that look to be in terrible shape often have the most pine cones.  



Is there a connection here?  Do dying pine trees actually produce a last gasp of cone production?  And if that's true, should I worry about those pine trees that suddenly produce a bunch of pine cones? 



I was also noticing this about the bougainvillea in my front yard.  As you can see, there are lots of flowers on it, but very few leaves.  



This is a beautiful plant, but it's not really very robust.  It SHOULD look like this (from the Carmel Mission, near Monterey, CA):  



This observation about the "tide in the affairs.." of plants leads to this week's SRS Challenge: 


1.  Does dying (or nearly dying) lead to a sudden efflorescence in plants?   
2.  If so, what causes this effect?  How does the plant "know" this, and respond? 
3.  Is this "sudden efflorescence" from a near-death experience true for any other plants?  


When I searched for this, I found that I had to learn a bit of language in order to make good queries.  

Let us know how you found the answers!  

I'll be back in a week (Wednesday, Nov 22) with my answer.  In the meantime, may you and all of your plants and trees be in good health.  


Search on! 


Tuesday, November 14, 2017

An itinerant scholar in the Age of the Internet


As you probably noticed... 

... I've been traveling a bit--hence the slightly erratic SRS posts over the past month. This will probably continue for a bit more time as I keep moving around the planet.  

  
Taveuni, Fiji


Both the springtime and the end of the year tend to be a busy time for me.  In the last 3 months of 2017, I will have visited Taveuni, Fiji; San Diego, CA; Washington DC; Pensacola, FL; Chapel Hill, NC; Knoxville, TN; College Park, MD; Cairns, QLD; Brisbane, QLD; Poughkeepsie, NY; and New York City, NY.


Pensacola, FL

This is what comes from being an itinerant scholar.  Even now, in the Age of the Internet and high bandwidth connections with live streaming 360-degree video, there's still an ineluctable value in actually being present.  



Why is that?  Couldn't I just phone (or video) it in?  

Knoxville, TN
As my friends Judy and Gary Olson wrote in 2000 paper, Distance Matters.  One of the more surprising findings from their studies is that people behave differently when they THINK you're far away.  It's a kind of unconscious bias: if I believe you're far away, then I tend to trust what you say less.  This is makes no rational sense, but it's been studied many times.  

What's more, when I visit you in your workplace (or university), we have the chance to have lots of informal, high-touch (notice I didn't say "high-bandwidth") interactions.  I've been in a lot of high quality videoconferences, but the quality of physical presence (with all of the nuances that seem to get lost over video) is powerful.  

UCSD, La Jolla, CA
What's more, when I visit you, we can have informal side discussions that are incredibly valuable.  When you're on a video call, the conversation is framed within the time of discussion--everything before and after (which turns out to be incredibly valuable) doesn't happen.  

Even though physically traveling to another venue is kind of a hassle--it's almost always worth it.  (Especially when that venue includes scuba diving, which doesn't work well over video...)  

Besides, when I travel, I pick up all kinds of ideas for SRS Challenges.  You'll be seeing a few during the next year!  

Me playing chess with statue. Georgetown, DC.
I think I'm winning.
In other news, I'm also trying to finish up my book.  I'm realizing just how much time writing a book takes.  Even if you've got over one thousand blog posts to draw from, editing some of them into a reasonable book takes a huge amount of sitting-and-typing.  

Thanks for hanging in there with me as I travel hither and yon.   It'll all be worth it! 




Still searching!  

















Reference:  Olson, Gary M., and Judith S. Olson. "Distance matters." Human-computer interaction 15.2 (2000): 139-178.

Wednesday, November 8, 2017

Answer: How many people die each year in the US?

How many and how people die,

.. it's complicated.  

More to the point, just figuring out which data sources you can trust for this kind of information is trickier than I would have thought.  



I asked you about your intuitions, and before I did any research on this, I wrote down a few of mine: 

     A. What fraction of people die from car accidents?  

     B. How many people die from other kinds of accidents?  

     C. How many people die of different medical conditions?  

     D. What are the leading causes of death?    

My guesses, before having done any research: 
A.  Car accidents:  15% of total deaths / year 
B.  Other (non-car) accidents:  5% / year 
C.  Medical conditions (not including old-age):  50%  
D.  Leading causes of death (of any or all causes), in order:              Accidents; Heart problems; Cancer


Let's see if we can answer these questions:  

1. How many people die (from all causes) each year in the United States?  

2. What are the top 5 causes of death in the United States?  (As a fraction of the whole.)  

As I mentioned, the interesting question is going to be:  Where do you get your data from, and why do you believe it's accurate?  

The obvious queries on different search platforms gives different numbers.  There's variation in the answers even within a single search platform.  Compare these results with slightly different queries on Google:   





Notice that there's a 250,000 person difference between these two numbers.  Why?  Because they come from different sources.  The first query gives a webanswer from a webpage at www.medicalnewstoday.com (which in turn gets its data from the 2014 CDC numbers), while the second query shows an answer that's from Quora.com with data from the UN data source, UNstats.un.org, and these numbers are from 2008.  

Oddly, the first article tells us that the CDC data is no longer available.  The link Medical News Today cites IS broken, but the obvious query: 

     [ CDC 2014 data deaths ] 

takes you to their "National Vital Statistics Report" which has exactly the same number: 2,626,418 in 2014. 

If you click on the Quora link in the second query [how many people die each year in the us], the writeup there takes you to the UN demographics report from October 2017, which tells us the total number of deaths for 2015. 

Looking at that page you see the entry for the US: 

From UN demographics report
READ CAREFULLY:  The Quora article says that "the most recent data available is from 2008."  But this data is from 2015 (the date is in the gray column), and the report was updated on 16 October, 2017... but notice that the number shown here is different from what's in the summary!  Here, the UN says it's 2,712,630 deaths in 2015. As opposed to the 2,473,018 deaths reported in the 2008 UN summary seen in the webanswer. Notice that we're comparing deaths in 2008 vs. deaths in 2015--of course there's a big difference.    

Think about what this means:  Of course, you'd expect the total number of deaths to change year-by-year: the overall population increases year-by-year, and the death rate changes as well... just much less than the overall growth in population.

Okay--so can we find the CDC data from 2015 to be comparable with the UN data?  

I noticed that in the CDC report we found above, the actual text in the paper was this: 
"In 2014, a total of 2,626,418 resident deaths were registered in the United States..." 
I know that these kinds of reports are often written from a template.  (That is, they probably just copied the report and plugged in the new numbers for 2015.)  So I did this query to find the report for 2015: 

     [ "In 2015, a total of * resident deaths" ] 

Notice that I changed the year to 2015 and used the * operator to match the new number for that year, and I double-quoted the whole thing to find a match for this exact phrase.  

Voila!  That takes me directly to the CDC report for 2015 where we find out that " A total of 2,712,630 resident deaths were registered in the United States in 2015."  

Let's compare these numbers from CDC and the UN: 
2014
UNC   2,626,418
CDC   2,626,418 
2015
UNC   2,712,630
CDC   2,712,630  
Notice anything odd about these numbers?  They're exactly the same!  If you go back a few years, you'll see more of this pattern. Which makes me wonder:  Where does the UN get their numbers?  From the CDC!  (After looking around, I found that nugget in a footnote, of course.)  

Which means that although we've "double sourced" this data, it's actually NOT double sourced--the UN is just taking whatever data the CDC hands them. 

You might be tempted to think that the UN is getting their data from a different US source; after all they give their data citation as coming from the "U.S. National Center for Health Statistics" in their "National Vital Statistics Report."  But when you look up the NCHS, you discover that they're a department of the CDC.  It turns out that they're the people who collect the data in the CDC!  

This is an interesting insight: the simple question How many people die each year in the United States? turn out to have a more complicated answer.  It varies by year, and as you might imagine, it varies depending on how you measure it.  

WHAT?  Isn't a death a death?  Can't you just count death certificates?  

Well, yes, but are you also counting people who disappear?  What about US citizens that die overseas?  Are they listed as a US death, or as a death in that country?  Are you counting from January to January, or just one month-long period and multiplying by 12?  Are abortions counted as deaths?  Stillbirths?  What about people in Puerto Rico, the US Virgin Islands and other territories?  (Why are the Virgin Islands broken out into a separate line item in the CDC report?)  What about military deaths in non-US locations?  

As often happens, once you start digging into a research question, you learn a lot about the area.  You learn the little details about your question that deepen your understanding of the question you're asking. This happens all the time when we do our SRS Challenges:  What starts out as a simple question turns into something larger and with more nuance than you thought at the start.  

In each of the questions I asked above, you can find the answers in the data commentary that's usually at the bottom of the data set.  (Sometimes it's scattered around in the text itself.)  But it looks like this, usually presented as footnotes: 


The notes describe the properties of the data: in this case, footnote #36 tells us that military and US civilians who die outside of the country are NOT included in the totals.  

In this case, we found out that which year you're asking about makes a big difference.  

What about that other question, causes of death in the US?  

Those same reports also break down the causes by percentages of all US deaths.  From the CDC report on health issued in 2017 (with data from 2015), we find that the top 5 causes of death in the US are: 

1. Heart disease (23.4%)
2. Cancer (22.0%)
3. Chronic Lower Respiratory Disease (CLRD) (5.7%)
4. Accidents (5.4%)
5. Strokes  (5.2%)

They illustrate this nicely with this chart (from the previous CDC reference):  

From CDC report, "Chartbook on Long-term Trends in Health"  pg. 18

As you can see, heart disease and cancer are the two largest causes of death, accounting for 45% of all deaths in 2015.  CLRD, the next most common cause, is only around one fourth as much.  

When I look back at my guesses (at the top of this post), I see my intuition was really wrong.  Accidents of all kinds are around 5.4% of the total (which means that car accidents are less than that).  

We may worry about mass murders or the latest version of flu, but the big killers each year are heart disease and cancer.  They are much more significant in terms of public health than anything else by far.  

When you look at the causes of death over time, it's a fascinating piece of data: 

Same source as above.  Notice that the Y-axis is a log scale, which means that a little big of change coming down (e.g., heart disease or stroke) is actually MUCH bigger than it might seem. That decline looks much less than it really is.  The improvement over 40 years is amazingly good.  Note also that CLRD is a new disease label that combines asthma, bronchitis, emphysema.  In 1999, the disease coding system changed to recognize those diseases as a cause of death, and separated out pneumonia and the flu into a separate category.

What is so striking is how constant many of these numbers of deaths are: Why do roughly the same number of people die each year in accidents? 

This chart also has good news / bad news: We're getting better at managing heart disease, but the overall cancer rate hasn't changed much in 40 years.  

And of course, another big factor in the causes of death is age at time of death.  People die of very different causes at different ages.  I saw a data table that suggested this, so I did the search to see if I could find a summary chart.  

     [ site:cdc.gov causes of death by age ] 

and found this chart in the CDC chart collection for causes of death, which shows how people die for very different reasons at different ages.  While cancer and heart disease are the largest causes of death, they come into play only after age 44.  Before 44, you're more likely to die of an accident.  



Search Lessons 


1. When looking at data, be SURE you understand WHEN it was collected and WHAT it's measuring.  As we saw, different sources (Alpha vs. Bing vs. Google) all draw on slightly different resources from different times.  This makes a big difference. 

2. Consider other factors that might influence your data.  In this case, death rates vary a LOT by age.  (They vary by other factors too, such as gender, race, and location--but I just focused on age in this post.)  Be sure you understand all of the aspects of the data that are important to you. 

3. When you need the "next document in the series," remember that those documents often use boilerplate language, which you can find with a fill-in-the-blank query, like  [ "In 2015, a total of * resident deaths" ].  This is an amazingly handy trick to remember.  

4.  Be sure you know where your data comes from!  I naively thought that the UN would have different data than the CDC--but noticing that their numbers are all the same drove me to check where the UN data came from... and it was... the CDC.  This data is NOT truly double-sourced!  




Search on!  


(I'll post a bit of background about why this one took so long to write up in my next post, later this week.  Let's just say travel go in the way.  And... I'll put out a new Challenge on Monday.  Stay tuned!)