Showing posts with label Correlation Does Not Imply Causation. Show all posts
Showing posts with label Correlation Does Not Imply Causation. Show all posts

Friday, May 21, 2010

Theories of Jupiter Cloud Belt Disappearance

On Facebook, Matt blames Earth's global warming for the disappearance of the Jupiter Cloud Belt. The data, however, makes me skeptical:
"The SEB fades at irregular intervals, most recently in 1973-75, 1989-90, 1993, 2007, 2010," said John Rogers, director of the British Astronomical Association's Jupiter Section. "The 2007 fading was terminated rather early, but in the other years, the SEB was almost absent, as at present."
Contra Matt, I would point to the fact that three of the first four SEB fades occurred during the year of a NBER business cycle peak: 1973, 1990, and 2007. Whether the Jupiter cloud belt is a lagging or leading indicator, I cannot be sure. Regardless, I think the writing is on the wall (er, Jupiter atmosphere) that we are about to experience a double-dip recession.

Wednesday, December 09, 2009

An Optimistic View of Taliban Pay

CNN:
"There is no set pay scale, but by our intelligence, they are paying the equivalent of about $300 a month and that is higher than we are paying Afghan army or police," McChrystal told the Senate Armed Services Committee, where he testified on Tuesday.
[...]
"In coordination with the Afghan government, we just almost doubled Afghan army and police training [pay]. It is in parity now. It is less than $300 a month but it's much closer," he told the committee.

"Almost doubling" indicates prior pay was in the neighborhood of $150 a month. It's no surprise then that the Afghan Security Forces have suffered from corruption charges and desertion– especially in the face of higher Taliban pay.

Anyone else find the news that the Taliban pay more than the Afghan Security Forces somewhat encouraging?

I do. The reason is because it gives us a clue about the direction of the compensating differentials. Like any organization with scarce resources, the Taliban probably only pays the competitive wage it needs to get the people they want. When the people they want are looking for employment, the Taliban finds itself needing to pay double the ASF to retain and attract. In other words, at the margin people would rather work for ASF than the Taliban (admittedly for reasons that are not necessarily ideological).

Again, I consider this good news because it revises my priors. True, the observed pay of the ASF may not match the actual compensation because of corruption and bribery, and so it could be that pay is roughly equivalent. However, corruption and bribery of ASF employees is not new information, as I think we all had a pretty good handle on the fact that this was occurring.

Tuesday, September 29, 2009

Books That Make You Dumb

To clarify, 'you' refers to your school and 'make you dumb' implies that the average ACT/SAT score is lower. Fortunately, 'books' is not a proxy; we are actually talking about books.

Nonetheless, you should check out this quick and dirty regression. The result: school's who prefer Atlas Shrugged to Fahrenheit 451 also report higher test scores.



[HT: Libby]

Monday, May 04, 2009

Blockquoting X

X=Fritz Machlup
Let us remember the unfortunate econometrician who, in one of the major functions of his system, had to use a proxy for risk and a dummy for sex.
HT: Roger Koppl (TAE comments)

Saturday, April 25, 2009

Sex, Lies, and Data

While sorting through the NLSY79, I realized women often answer one particular question inconsistently from year to year.

How old were you when you first had sexual intercourse?

A subset of the 79 cohort was asked this question in 1983, 84, and 85. More often than not, they answered inconsistently. 1 year differences could probably be chalked up to natural error. "Was I 16 or 17 that Summer?" What do you say for a 16/20 split though? Clearly, someone is not telling the truth. But why lie to an interviewer?

After skimming the NLSY79 manual, it appears as the interviewee was not always surveyed alone (spouses, children, etc. were present). That's unfortunate, from a scientific perspective. I plan to use the lowest year offered by the interviewee. What do you think?

(The question was not repeated for males once they had offered a year, so comparisons are not possible.)