Innumerate Claim of the Day: NASA Scientists Dispute Climate Change

So I get this email from a colleague today offering me “proof” that global warming is a scam. His “overwhelming evidence”?

A letter from 49 former NASA Scientists. NASA is in open revolt over climate change!

Wow, 49 Scientists? That’s really impressive (at first glance!) Let’s see if it holds up to scrutiny.

Whenever I see a single number out of context, it makes my Spidey sense twitch. What is the significance of subset 49? What is the parent set —  50? 100? 1000? 18,000? 50,000?

To put this into some context, let’s look at the data. NASA currently employs 18,000 people. In the 1970s, half of their employees had professional degrees. Let’s ballpark it down to about a third of these folks today are scientists or engineers. Since NASA began in 1958 with 8,000 workers, they have many tens of thousands of employees. I can’t guess how many — 40,000, 50,000 people? And many of those were scientists and engineers.

Of all these people, living and dead, 49 got together and wrote a letter.

Now that we have some context, that strength of the initial participation looks rather silly. These 49 people — only one of whom is an actual meteorologist — are an extremely tiny percentage of current (or former) NASA Employees.

I am always suspicious when I see as single number out of context. It often serves as a tool for deception.

Just another example of confirmation bias at work.

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Previously:
Statistics: Scientific Consensus on Climate Change? (December 31st, 2009)

Source:
49 Former NASA Scientists Send A Letter Disputing Climate Change
Gus Lubin
Business Insider, Apr. 11, 2012  
http://www.businessinsider.com/nasa-scientists-dispute-climate-change-2012-4

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