Chance to ask me a question this Friday
Dampened by Google

Maxima and minima

Andrew Sullivan (link) highlights the insanity of the law with this "Chart of the Day", except that chart fails to bring out the message:


For this data set, a Bumps-style chart works very well:



The bar chart uses the wrong minima. Bar charts encode data in the lengths of the bars. When an equal length is chopped off the base of the bars, the relative lengths are distorted.

In the case of Ecuador, it appeared as if murderers get half the sentence as drug traffickers, when in fact the difference is 25 percent.

The chart also obstructs readers from comparing sentences across countries. That must be why the 16 years in Ecuador has the same length as 25 years in Bolivia. Either that, or time runs faster in Bolivia (and Mexico).


The Trifecta checkup (link) reveals that the biggest problem is the misalignment between the question being asked and the data used to address that question.

It's hard to imagine why the "maximum" sentence is considered, rather than, say the average sentence. If the analyst chooses maxima, he/she should assure readers of a couple of things: that the judges in these countries do apply the maximum penalties, and that the proportion of sentences that reach the maxima is roughly similar between drug traffic and murder cases.

I suspect the use of maxima is related to data availability. To compute the average or median sentence requires data on every conviction that leads to a prison sentence. To find out the maximum sentence only requires consulting a book. Is there any real data on the chart? It depends on whether any of these countries routinely dole out the maximum sentence.

Then, there are cases involving both drug trafficking and murder...


ezra abrams

ezra abrams

Respecfully, this is what is wrong with the huge amounts of blogging on charts.
You assert that one is better, but have no data (in contradistinction to clevelands 45o rule - he actually had data on how people percieve stuff)
me personally, i found the bar chart much more clear
a lot of that has to do with what people are expecting; a chart that might, in theory be better, is worse if people are not used to it.

But the main point is, respectfully, your opinion is just that - your opinion.

I have noted. over the last few years, that scattered about a very, very diverse literature is a lot of info on experiments that rarely makes it into the blogs on graphs.

to make a pos could have put up the two graphs, wiht min comment, and asked readers to prefer one.
I don't know how many people come to this blog, but that would be a nice data set; with some sophistication, you could even randomize the order in which the graphs are presented

ps: it is confusing to have the comments link separated from the article by a horizontal bar..could use some better clarity onyour blog there


While we might not know the average sentence, isn't it interesting to see the divergence in the maximum sentence for crimes of drugs and murder? In each case murder has a maximum less than drug crimes! That seems pretty important, and crazy!


Henry: When Sandy left lower Manhattan without power for a week last year, I had to check into a hotel. Got majorly gouged, six hundred per night for a small room in a holiday-inn standard hotel. I checked the door to look for the "rack rate". It said "This room may not be charged for more than $750 per night."

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