Skepticblog

Estimating the number of people who have
experienced the paranormal or supernatural

The Drake Equation is the famous formula developed by the astronomer Frank Drake for estimating the number of extraterrestrial civilizations:

N = R × f_p × n_e × f_l × f_i × f_c × L where…

• N = the number of communicative civilizations,
• R = the rate of formation of suitable stars,
• f_p = the fraction of those stars with planets,
• n_e = the number of earth-like planets per solar system,
• f_l = the fraction of planets with life,
• f_i = the fraction of planets with intelligent life,
• f_c = the fraction of planets with communicating technology, and
• L = the lifetime of communicating civilizations.

The equation is so ubiquitous that it has even been employed in the popular television series The Big Bang Theory for computing the number of available sex partners within a 40-mile radius of Los Angeles (5,812). My favorite parody of it is by the cartoonist Randall Munroe as one in a series of his clever science send-ups, entitled “The Flake Equation” (on xkcd.com) for calculating the number of people who will mistakenly think they had an ET encounter.

Such multiplicative equations for calculating the product of an increasingly restrictive series of fractional values are effective tools for making back-of-the-envelope calculations to solve problems for which we do not have precise data. To that end I thought it a useful addition to the Skeptic toolbox to create a Flake Equation for all paranormal and supernatural experiences (and in the Flake Equation I’m interested not in beliefs but in actual experiences that people report and that we hear about, because this becomes the foundation of paranormal and supernatural beliefs):

N = P_w × f_p × f_m × f_t × n_t × n_o × f_m where…

• N = Number of people we hear about who report having experienced a paranormal or supernatural phenomena,
• P_w = Population of the United States (January 1, 2012: 312,938,813),
• f_p = Fraction of people who report having had an anomalous psychological experience or witnessed an unusual physical phenomena (1/5),
• f_m = Fraction of people who interpret such experiences and phenomena as paranormal or supernatural (1/5),
• f_t = Fraction of people who tell someone about their experience (1/10),
• n_t = Number of people they tell (15),
• n_o = Number of other people told the story by original hearers (15), and
• f_m = Fraction of such stories reported in the media or on Internet blogs, tweets, and forums (1/10).

N = 28,164,493, or about 9 percent of the U.S. population.

To compute this figure I used the 2005/2007 Baylor Religion Survey, which reports that

• 23.2% say that they have “witnessed a miraculous, physical healing,”
• 16.3% “received a miraculous, physical healing,”
• 27.5% “witnessed people speaking in tongues at a place of worship,”
• 7.7% “spoke or prayed in tongues,”
• 54.5% experienced being “protected from harm by a guardian angel,”
• 5.9% “personally had a vision of a religious figure while awake,”
• 19.1% “heard the voice of God speaking to me,”
• 26.1% “had a dream of religious significance,”
• 52% “had an experience where you felt that you were filled with the spirit,”
• 22.1% “felt at one with the universe,”
• 25.7% “had a religious conversion experience,”
• 13.8% “had an experience where you felt that you were in a state of religious ecstasy,”
• 14.2% “had an experience where you felt that you left your body for a period of time,”
• 40.4% “had a dream that later came true,” and
• 16.7% “witnessed an object in the sky that you could not identify (UFO).”

This works out to an average of 24.4 percent, thereby justifying my conservative 20 percent figure for f_p and f_m. The other numbers I gleaned from research on gossip and social networks, conservatively estimating that 10 percent of people will tell someone about their unusual experience, and that within their average social network of 150 people they will tell at least 10 percent of them (15) who in turn will pass on the story to 10 percent of their social network of 150 (15). Finally, I estimate that 10 percent of such stories will be reported in the media or recounted in blogs, tweets, forums, and the like.

Of course the final figure for N will vary considerably depending on what numbers are plugged into the equation, but the result will almost always be a number in the tens of millions, which goes a long way toward explaining why belief in the paranormal and supernatural is so ubiquitous. Experiencing is believing!