Record Mathematics, Part II
In my last post, I explained why record temperatures are no big deal. In short, this is because the recorded history is so small (~100 years), and there are so many categories (two or four for each day of the year). Of course, analyzing weather trends is big now, in the context of global warming, and obviously a warming trend would be reflected in more record highs and fewer record lows than you would expect if the trend was flat. My main point was that the expected number of records being set for even a flat trend is a lot higher than most people would have guessed.
I’m hardly an expert, I can see why proving that global warming is real can be so slippery: not enough recorded history and too much natural variation. I personally believe that global warming is something we should be more concerned about than we currently are, but that comes not from having looked at data to draw my own conclusions, or from personally experiencing the climate, but more from trusting the mass of scientists who do look at the data.
And not to beat up on the global warming crowd, but as long as I’m on the subject, check out this quote:
from http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=609&tstamp=200701 (which has some interesting charts, by the way).
Sounds significant. Maybe it is , but note the appearance of the somewhat unusual number ‘15’. That always throws a red flag in my mind – what sort of mining has been done to produce the most dramatic statistic. I mean, if you didn’t know the end result, you would probably pick rounder numbers, like 10, 20, or even 25. Why 15?
The worst place to see records found from mining is in sports. I’ve noticed more and more in the last few years sportscasters talking about records like “that team is the first in the last 31 years to average 300 passing yards a game over a five game span while holding the opponent to under 85 rushing yards.” Not only is that a mouthful, but the large number of variables makes for a massive number of record categories. It’s completely unexceptional that some of them get broken each year. I tune those records out.
I’m hardly an expert, I can see why proving that global warming is real can be so slippery: not enough recorded history and too much natural variation. I personally believe that global warming is something we should be more concerned about than we currently are, but that comes not from having looked at data to draw my own conclusions, or from personally experiencing the climate, but more from trusting the mass of scientists who do look at the data.
And not to beat up on the global warming crowd, but as long as I’m on the subject, check out this quote:
Six of the ten warmest U.S. winters on record have occurred in the past 15 years
from http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=609&tstamp=200701 (which has some interesting charts, by the way).
Sounds significant. Maybe it is , but note the appearance of the somewhat unusual number ‘15’. That always throws a red flag in my mind – what sort of mining has been done to produce the most dramatic statistic. I mean, if you didn’t know the end result, you would probably pick rounder numbers, like 10, 20, or even 25. Why 15?
The worst place to see records found from mining is in sports. I’ve noticed more and more in the last few years sportscasters talking about records like “that team is the first in the last 31 years to average 300 passing yards a game over a five game span while holding the opponent to under 85 rushing yards.” Not only is that a mouthful, but the large number of variables makes for a massive number of record categories. It’s completely unexceptional that some of them get broken each year. I tune those records out.
posted by Jim at
9:36 PM
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