Wednesday, March 26, 2014

The Signal and the Noise #2


As I am about halfway done The Signal and the Noise, I must say that I am thoroughly enjoying it, and it thus far has been my favorite book I have read for this blog. Nate Silver, due to his background as a statistician rather than a writer (See first post for this blog) brings a very unique writing style to the book. I find it very interesting to read about the unique viewpoints he looks at things through. In his opening chapter, he talks about Johannes Guttenberg, he then goes on to talk about how Guttenberg had invented the printing press. His reasoning for telling the story of Guttenberg was, as Silver says on page 2, “Johannes Guttenberg’s invention in 1440 made information available to the masses, and the explosion of ideas produced had unintended consequences.” Silver is that the printing press led to a spike in information which in effect led to a spike in technology which increased the amount of information we have today, but the unintended causes is that today we have more information than we need when solving the majority of things.  With a plethora of information today, we need to be able to separate the information that is real evidence, which he refers to as the signal, and the information that distracts us from the evidence, which he refers to as the noise. Silver uses this book to analyze people’s predictions. He focus on wide variety which jumps from predictions about what the economy will do, what Dustin Pedroia will do in his baseball career, what the weather will be like, to the chances of an earthquake happening.

 I particularly enjoy the similes and analogies he uses to illustrate complicated events in simpler way. In example of this would be why house prices had increased such a huge amount and made them unaffordable to many Americans. He introduces the terms negative and positive feedback. To describe negative feedback, his example is kids running a lemonade stand, and if kids across the street open up a stand, the price of the original stands lemonade will more than likely go down due to competition. This would be an example of negative feedback, and then he describes the housing industry as having positive feedback, as to determine the price of house, we often use comparisons, so if one house’s price rises, another few probably will, which will cause another few after that, until the price of the average home has skyrocketed and the market has imploded. He humorously states the effect of positive feedback on a lemonade stand, writing on page 30, “Eventually you’re charging 46,000 for a glass of lemonade-the average income in the United States each year-and all 300 million Americans are lined up around the block to get their fix.

 I also think he does a very good job of describing how “the noise” is very often our own human bias. He describes on page 137, with a graph, he how weatherman often will stray from predicting there is an exactly 50% chance of rain, as then it is a toss-up and the listeners will be disappointed they won’t know if it will rain tomorrow. Silver also had discovered that when there is a 50% chance of rain and weatherman don’t want to say 50%, they will more often than not go to 60%. The reason behind this, as Silver explains, is that if you say it probably isn’t going to rain and it does, then you ruin everyone’s picnic, however if you say it’s going to rain, and it doesn’t, then people are delighted and view it as an “extra” day of sunlight.  

                  

             (Prediction on X axis, actual result on Y axis)

He also mentions how on a TV show which features former politicians debating what will occur next in political races, they often tend to dramatize for the television. For example, Silver found out that if one guy said that something was certainly going to occur, it would only occur about 75% of the time. He also keyed in on an episode in the week leading up to the Obama-McCain election, in which out of the four contestants, only one said Obama would win in a large margin, as he was favored to and as he did, and the other three either gave Obama a slight advantage or said it was too close to call. Their goal of this, as Silver writes, is to make it seem the race is much closer than it actually is, so people will continue to tune in to hear updates.

This book is similar to Malcolm Gladwell’s books, however, rather than scientific studies, this book is a lot more statistically and mathematically focused, as many of the chapters are filled with graphs, charts and tables. However, I think he uses graphs, charts and tables very effectively. A great example of this is on page 81-83, in which he presents two graphs of the average baseball player’s performance in relation to his age. He first presents a graph that would accurately represent the curve that a player goes through as he rises at a younger age until about 27 years old, and then they start to decline. Then, two page later he presents a “noisy” graph that is misleading and that you cannot draw as many conclusion from.




(Accurate graph on the left, noisy graph on the right)

  As I had stated earlier, I am greatly enjoying this book and I look forward to finishing it.

 

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