Doing legwork, doing justice
Spin, spin, spin away

Two unhealthy submissions from readers

Abc_birdfluJosh hated this "dataless visualization" from ABC. (link; warning: ads). Here are his comments:

The report has planes leaving China, landing across the globe and instantly infecting us all with bird flu.  It doesn't do a good job explaining how and the rate pandemics actually spread.  However, it does do a good job scaring us all.

The entire flu pandemic theater is unscientific. It is based on the 100-year flood type of argument, with scientists claiming that we are "overdue" for some catastrophe. Reminds me of earthquake forecasting, covered by Nate Silver in his book. It is possible to predict the average frequency of, but virtually impossible to predict the timing of rare natural disasters.

The 100-year flood type calculations is based on averaging a small number of events over a very long time scale. There is no reason why these events should be spread out evenly over time (i.e. one event every 100 years).

This is a fallacy of "law of small numbers": if one throws a fair coin 10 times, one shouldn't expect exactly 5 heads, as the distribution of heads should look like the chart on the right. The chance of exactly 5 heads is only 25%.

Binomial

Also, doctors keep me honest but I believe only one type of mutation, i.e. the one that makes the virus able to pass from human to human, has a chance of causing a pandemic. So it is wrong to say that "if the virus mutates," a pandemic will result. In addition, in the past, some viruses were able to pass from human to human but the rate of infection was not fast enough, and they failed to lead to a pandemic.

***

Daniel L. did not like the map shown below, from a research article on female mortality rate in the U.S., via Jezebel.

I was amused by what the blogger at Jezebel was able to take in from the map. Her post started with a huge version of the map, under which she said:

Mortality rates are rising in 43% of U.S. counties, as illustrated by this map from health researcher Bill Gardner.

Femalemortalitymap

Mortality rate is a statistic about the population. The map is an illustration of geographical area (distorted by the map projection). The map carries no information about population at all. Thus, it is not the right chart to display population data.

The statistic itself is poorly chosen. What does 43% of counties mean? Some counties have few people while others are very densely populated. New York County is barely visible on this map yet it has the heaviest weight on the average. 

According to the CDC data, the death rate, age-adjusted, for women has been decreasing over time. So, the backward motion in those 43% of counties is somehow compensated for by forward progress in the other 57% of the counties, it appears.

Cdc_deathratebygender

Maybe the average for the whole country masks some local patterns. The cited map doesn't help because it assumes that the importance of the mortality rate is proportional to the geographical size of the county, when the right comparison should be the population of women in the county.

 

Comments

zbicyclist

"New York County is barely visible on this map yet it has the heaviest weight on the average."

Not to be nitpicky, but New York County is not the largest county in population. It's the 20th largest. You are perhaps confused by Saul Steinberg's "map".

http://bigthink.com/strange-maps/72-the-world-as-seen-from-new-yorks-9th-avenue

Kaiser

I was confused by Wikipedia! They say "New York County is the most densely populated county in the United States". link Probably shouldn't trust Wikipedia.

Roger

You are arguing two different things, NY county can be both "the most densely populated" and "the 20th largest county in population".

Kaiser

Roger: Good catch. I thought I posted a note at 3:22 when I realized I read "most populous" rather than "most densely populated" but the note is lost in cyberspace.

Floormaster Squeeze

Mortality rate is the number of deaths per some measure of the population. A mortality rate can go up without their being more deaths. It can also go up because the average age of the population is going up.

I suspect a big reason 43% of counties have increasing death rates is because they are losing population and more specifically losing younger population (which changes the average age and the expected death rate). That is, this 43% factoid is about demographics not life expectancy.

Now, if an age-adjusted death rate was going we would have news.

ezra abrams

this is the second bronx justice story the times has done in the last year (the last one was about elevators)

Both Stories are outstanding, journalism at its very best.

the least you could have done was acknowledge that this is truly great reporting - i think you should be ashamed for not pointing this out to your readers

I think you are also derelict in not pointing out to your readers taht the Times has had some truly *outstanding* graphics on its website in the last year or two; instead of just criticizing, you should point out to your readers the gems of web graphic

Kaiser

Ezra: Did you put the comment on the wrong post? The charts on this post did not come from the Times.

Also, the blog from Day 1 has the point of view that graphics production involves tradeoffs - even "good" graphics have weaknesses and I like to discuss different ways of visualizing the same data.

It is true that 99% of what I receive from readers are things they do not like. The only way to change that is if people like you send me graphics that you consider to be good. So why don't you send me some examples?

Andrew Couch

I'm somewhat confused why you're so derisive of this choropleth map. In other places you've described such visualizations as "engaging".

Your complaints "distorted by the map projection" and "proportional to the geographical size" could be said of any such chart. Sure, scaling the area to match population adds a dimension, but you must admit that it comes at the cost of reader understanding.

The comments to this entry are closed.