Archive for October, 2012

Probability of vote being pivotal is so small it’s not worth voting

That was the view of 2nd-year PhD student Douglas VanDerwerken up until this Presidential election.  He abstained on the basis of the lack of return on investment for spending the time to vote when it really cannot make a difference.  VanDerwerken lays it all out for statistics magazine Significance in an article for their current (October) issue.*  According to his reckoning, there is less than one chance in a million (4.5×10^-7 to be precise) of any person’s vote having an impact.  This would be a situation where the voter lives in a swing State and the election comes to a dead heat.

Fortunately (in my opinion—being one who views it as a civic duty) VanDerwerken had an epiphany based on moral reasons, so he shall vote.  Thank goodness!

“If you think about it, voting in a large national election – such as the US Presidential election – is a supremely irrational act, because the probability that your vote will make a difference in the outcome is infinitesimally small.”

– Satoshi Kanazawa, rational choice theorist**

* “The next President: Will your vote decide it”

**See Kanazawa’s three-part series on “Why Do People Vote” for his blog “The Scientific Fundamentalist” hosted by Psychology Today. Start with Part 1 posted here and continue on to the end for the answer.

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Time to lighten up on homework?

The Wall Street Journal’s Market Watch this Friday posted the data shown in this chart.  For the 11 countries shown** you can see why WSJ seconds the call by French President Hollande to ban all homework.

Students would party hearty but this laissez-faire approach will not fly with those blessed with ambitious parents.  Nevertheless the call for less homework, fueled by new data from the National Center for Education Statistics, reinforces other studies going back at least a decade.

It will be interesting to see what emerges as a consensus for a the happy medium on amount of homework assigned.   Four hours per night seems way too much, especially at the 8th grade level.

Meta-analysis of hundreds of studies done on the effects of homework shows that the evidence supporting the practice is, at best, modest. Homework seems to be most useful in high school and for subjects like math. At the elementary school level homework seems to be of marginal or no academic value.

– Malcolm Gladwell

*See the report here

**I took out Saudi Arabia, whose result of 34% below average, given 11% being assigned over 4 hours of homework per night, fell far below even these very off-putting predictions–an outlier statistically.

Acknowledgment: Thanks to Devan Govender for alerting me to this issue.

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USA unemployment statistic creates a sensation

“Unbelievable jobs numbers..these Chicago guys will do anything..can’t debate so change numbers.”

– Jack Welch

Thursday morning I attended a briefing on the economy by an expert from Wells-Fargo bank.  Looking over the trends in USA unemployment rates he noted that no incumbent since World War II has achieved re-election when joblessness exceeded 8 percent.  Friday the Bureau of Labor Statistics (BLS) announced that the the national unemployment rate is now 7.8%, an improvement from 8.1% last month.    How accurate is this number and is it precise enough that a 0.3% difference can be considered significant?  I agree with the conclusion of this critique posted by Brookings Institution  that “a large part of monthly unemployment fluctuations are spurious.”  So, really, all this fuss about it being 8.1 versus 7.8 percent is really silly from a statistical point of view.  However, it is entertaining!

 

 

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Rock on with algorithms?

I started off my career as an experiment designer before the advent of cheap calculators.  Paying $400 for an HP unit that (gasp!) did logarithms went far beyond my wherewithal in 1974.  That was roughly the tuition for one college quarter at University of Minnesota if memory serves.  I managed to cover that cost plus room and board by working 24 hours a week washing pots and pans at a hospital kitchen.  Those were the days!

Calculating effects from the two-level factorial designs I did that summer as an intern at a chemical research lab required a lot of hand calculations—many numbers to add and subtract.  Thankfully a fellow named Yates developed an algorithm after these experiments were invented in the 1930s.  Following his directions one could tally things up and even do check sums without having to think much.  That’s what algorithms do—provide a recipe for solving problems.

As an engineer I have a healthy respect for algorithms, but my wife, who works as a preschool teacher, thinks this is geeky.  For example, I admired the nerdy professor in the TV show “Numbers” that aired a few years ago.  But every time he expounded on some algorithm that ingeniously saw the pattern of a serial criminal, she just laughed.  Ironically she is now hooked on a show called “Person of Interest” that is based on predictive policing, that is, using algorithms to calculate a crime to come.  That scares me!

According to a new book by Christopher Steiner titled Automate This: How Algorithms Came to Rule Our World (see this Wall Street Journal review) all of us had best be on our guard against seemingly clever ways to systematically solve problems.  It seems that the engineers, mathematicians, programmers and statisticians who come up with these numerical recipes invaded Wall Street.  They became known as the “Quants”—dominating the way stocks now get traded.

The problem with all this (even I have to admit) is that these systematic approaches to things take all the fun out of making choices.  Do we really want algorithms to pick our soul mates, invest our money, etcetera?  I am up for algorithms like Yate’s that quickly solve mathematical problems.  A good example of this is the first known algorithm recorded on clay tablets in 2500 B. C. that helped Sumerian traders divvy up a given amount of grain equally to a varying number of recipients.  However when things become capricious with many unknowns that are unknowable being thrown into the mix, I’d rather make my own decisions guided by wise counsel.

There is an elephant in the room whenever it comes to discussing computer algorithms, particularly highly automated ones. Almost all such algorithms are inaccurate. They are inaccurate for many reasons, the most important of which is that human behavior is fickle. The inaccuracy could be shockingly high.

–          Kaiser Fung, author of Numbers Rule Our World

I really shouldn’t bring this up, but do you suppose certain politician might be spending a lot of money on algorithmic solutions to how they can win election?  Do these algorithms have any qualms about turning their protagonists into nabobs of negativism?  I do not believe that an algorithm has any heart, unfortunately.  An algorithm is like Honey Badger—it just don’t care.

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