Interesting information about underground power lines

There's been a lot of talk in recent weeks, after the large storms that disrupted power in several mid-Atlantic states, about the prospect of burying power lines. Overall, according to the Edison Electric Institute, about 18% of distribution line mileage is underground. (That's the small lines that go to your house, not the big transmission lines. Of those, about 0.5% of mileage is underground). The chart above, a screenshot I took from The US Energy Information Administration site, tells why: it costs considerably more to run new distribution lines underground, or to convert overhead lines to underground, than it does to install new overhead lines. As I read the chart, considerably more means four times as much per mile, though according to accompanying article it's "up to five to ten times more..."

What accounts for the difference? It's partly the circumstances - what's under the ground: granite? Water? And there's a cost for dismantling overhead lines during the replacement. But part of the difference is the graininess of the charts - I mentally rounded up the cost of new overhead lines to $500/mile, and rounded down the costs of new underground or conversion costs to $2000. That makes sense based on the charts, given the $500 increments. But if the chart and the text are that different perhaps there's something wrong with one of them. Notice also, about the chart, that the bars do not go all the way down to the x-axis, but float a little above it.

Two good stats articles from the NY Times

OK, I spend a fair amount of time on this blog making fun of the NY Times' statistical reporting. So today, two articles where the Times does a good job explaining, reporting, and illustrating statistics.

I thought the Times did a great job explaining the census data released this morning, which show that 50.4% of the US population younger than age 1 are minorities as of July 1, 2011. Interestingly, when I read the Census Bureau press release, I learned also that there are four majority-minority states (Hawaii, California, New Mexico, and Texas). The District of Columbia is also majority-minority. I did think that the Times' graphic illustrating Generational Gaps in Minority Births was confusing (screenshot below). A better title might have been "States with Largest Generational Gaps in White Population" because that is what I think the graphic shows.

Source: The New York Times
I would also quibble with the "tipping point" characterization of the births graphic illustrating the article.
Any thoughts about this? Let me know in the comments.

In a different kind of article, I thought the Times did a very thorough job of explaining new research on HDL, "good cholesterol" and why simply raising HDL may not prevent heart disease. The story is a good illustration of the point that I've made and reiterated about using statistics: correlation and causation are not the same thing. I've just begun reading Jim Manzi's book "Uncontrolled," (I'll be writing more about that later). The episode is a good illustration of the progress of scientific knowledge he describes in his third chapter.

Improving data displays

I've just come across a website, Junk Charts, that illustrates and identifies some of the many problems you can stumble across illustrating data using charts. It's a very useful resource, as the author Kaiser Fung always explains what is wrong with each chart and illustrates how to do it better. Take a look at his post on the USDA's pie chart explaining healthy diets, here, for example.

And here's a screenshot of another, one where Fung argues that pie charts should be abolished.

And a final example, in which Fung illustrates exactly whose taxes would be lower under the 9-9-9 proposal (hint: it's not who you might think).

Altogether, an entertaining and instructive site.