Let’s Do the Math

• P_gp (1.2% in 2008) is the percentage of the general population who are psychopathic
• P_gi (0.94% in 2011) is the percentage of the general population who are incarcerated
• P_ip (20% in 2001) is the percentage of the incarcerated population who are psychopathic

By failing to disambiguate these statistics from one another, we leave them open to tacit dismissal.  “At 20%, it looks like most or all of the psychopaths are in prison,” one might take away from these statistics.  “Good job.”  These statistics by themselves leave the whole problem of psychopathy in society too easy to dismiss out of hand because they do not describe the demographics fully enough.  Most people desperately want to dismiss the problem out of hand because accepting it as a basic social problem saddles each and every one of us with a basic social responsibility that most of us don’t want anything to do with.

Let’s take this excuse away.  Let’s do the math it takes to finish the picture.  Let’s calculate P_pf, the percentage of the psychopathic population who are free to wander among us and prey upon innocent victims, deprive them of their basic human rights and turn their lives into living hells, for lack of public awareness with all but total impunity.

Formula Components

• P_gp = Percentage of the GENERAL population who are psychopathic
  • 1.2% of the general population are psychopaths – http://en.m.wikipedia.org/wiki/Psychopathy
  • This article does not say whether the 1.2% figure from “a US sample” covers ALL Americans or only those not incarcerated.
  • The present calculation assumes the former; a separate calculation shown below assumes the latter and results in an even higher value for P_pf.*
• P_gi = Percentage of the GENERAL population who are incarcerated
  • 0.94% of the US population are in prison – http://en.m.wikipedia.org/wiki/Incarceration_in_the_United_States
• P_ip = Percentage of the INCARCERATED population who are psychopathic
  • 20% of a typical US prison population are psychopaths – http://www.hare.org/links/saturday.html

Additional Results

• P_gpi = Percentage of the GENERAL population who are both psychopathic and incarcerated
  • P_gpi = P_ip x P_gi = 20% x 0.94% = 0.188%
• P_gpf = Percentage of the GENERAL population who are psychopathic but FREE
  • P_gpf = P_gp – P_gpi = 1.2% – 0.188% = 1.012%
• P_pi = Percentage of the PSYCHOPATHIC population who are incarcerated
  • P_pi = P_gpi/P_gp = 0.188%/1.2% = 15.667%

The Result We’re After

• P_pf = Percentage of the PSYCHOPATHIC population who are FREE
  • P_pf = 100%-P_pi = 100% – 15.667% = 84.333%

Formula for Calculating P_pf

• P_pf = 100-P_pi
  • = 100-[(P_gpi/P_gp)*100]
  • = 100-[((P_ip*P_gi)/P_gp)*100]
  • = 100-[((0.2*0.94)/1.2)*100]
  • = 100-[(0.188/1.2)*100]
  • = 100-(0.15667*100)
  • = 100-15.667
  • = 84.333%

* Changing our assumption about the 1.2% figure for psychopaths within the general population to exclude those incarcerated, the calculation is slightly revised, though the formula remains the same.

• P_gp becomes 1.2% + (P_gi x P_ip) = 1.2% + P_gpi = 1.2% + 0.188% = 1.388%.
• The final calculation of P_pf then increases from 84.333% to 100-[(0.188/1.388)*100] = 100 – 13.545 = 86.455%.
• P_gpf is then 1.2% (the figure quoted in the article) rather than 1.012% resulting in a proportionally higher average expected encounter rate within the general population.

Discussion

84% to 86% of all US psychopaths are NOT in prison, representing 0.972% to 1.2% of the unincarcerated population. Depending on a typical working American’s profession or line of work, that could expose them to anywhere from 2 or 3 encounters per week to 2 or 3 encounters per day.  For those more apt to be profiled during such encounters as both accessible and vulnerable targets, each encounter with the same psychopath leads to more and more encounters going forward.

My own experience has been that psychopaths who know about each other tend to take turns with a given target rather than interfere with one another. Everything they do is based on the fabrication and implication of misleading impressions about themselves and about their victims. They would not be able to do this effectively if they presented conflicting false impressions of the same victim or if they had to coordinate with one another to maintain their consistency. In clinical terms, a psychopath must build and maintain his or her psychopathic fiction in isolation from those of other psychopaths. They cannot therefore share victims lest these fictions collide around a shared victim. Psychopaths are very good at reconciling such collisions to satisfy those who notice them but steering and avoiding the aegis of other psychopaths reduces their workload as it reduces their risk of exposure. There is also the question of the psychopathic bond, whose strength might be broken or even canceled when compounded in the same person at the same time by different psychopaths.