Give this a thought—when the NSA sorts through American communications to find a terrorist, what is their real accuracy in finding one? Could a “false positive” result? This is an erroneous ‘positive’ diagnosis resulting from testing inaccuracies. Now, wrap your mind around this—the NSA test will accurately measure 99 percent of terrorists who take it, but that doesn’t mean that 99 percent of ‘positive results’ are terrorists.
Just how rare are terrorists in America? Between 2001-2011, there were 207 attempted terrorist attacks within the United States, which is an average of about 20.7 per year. If we assume there were about 20 individuals involved per attack, that would mean there were 414 terrorists in America per year. Based on this, one in every 624,297 Americans is a terrorist.
With a little help from Bayes Theorem, we can determine there’s a 99.98416 percent chance of a “false positive” occurring—probability of not being a terrorist given a ‘positive’ test result. This means there’s just a 0.01584 percent probability of being a terrorist given a ‘positive’ test result. Surprised by this? The higher the rarity, the more false results, even despite an accurate test.
The bottom line for you is simple: when it comes to living online, never say anything (NSA)! To learn more, check out the infographic below.