The further information given on the page the article links to is still woefully incomplete. As a rule of thumb, I would be immediately suspicious of any data analysis expressed so ambiguously. They do mention the numbers come from a CBO report, so maybe the details are available elsewhere, but as presented, there are a lot of assumptions and omissions (for example, looking at the numbers, it seems reasonable to assume that 'average' is taken to be the mean, but this is a really basic distinction, especially since it is quite common to see medians given for incomes precisely because the means are so skewed) that give the impression (confirmed by googling their names) that the article written by lawyer/sociologist types, rather than by statisticians, and furthermore, that whoever wrote it is trying to fool me. Also, fourth fifth is a funny name for a category.
I could not find out whether or not the "average" they used was the mean, I admit. However, one can say with reasonable certainty that it is not the median that they use in that data. If you look at the 2005 supplemental data, the median after-tax income was $55900. However, in the data, the average they list for all households is $67400.
Comments
As a rule of thumb, I would be immediately suspicious of any data analysis expressed so ambiguously. They do mention the numbers come from a CBO report, so maybe the details are available elsewhere, but as presented, there are a lot of assumptions and omissions (for example, looking at the numbers, it seems reasonable to assume that 'average' is taken to be the mean, but this is a really basic distinction, especially since it is quite common to see medians given for incomes precisely because the means are so skewed) that give the impression (confirmed by googling their names) that the article written by lawyer/sociologist types, rather than by statisticians, and furthermore, that whoever wrote it is trying to fool me.
Also, fourth fifth is a funny name for a category.
is the report it comes from, presumably.
http://www.cbo.gov/doc.cfm?index=8885
for the year after it.
I could not find out whether or not the "average" they used was the mean, I admit.
However, one can say with reasonable certainty that it is not the median that they use in that data.
If you look at the 2005 supplemental data, the median after-tax income was $55900. However, in the data, the average they list for all households is $67400.