armysgt wrote on Dec 16
th, 2007 at 3:50pm:
Why do Law Enforcement agency re-lie so much on the poly and not the back ground? It seems to me that they are losing a lot of good people on a machine that is maybe 87% to 93% effective. Now I understand why so many departments are not meeting there hiring quotas. I believe a good back ground will reveal more than a machine with a low percentage rate.
Excellent question,
As a former background investigator and current polygraph examiner I feel fairly qualified to answer your question.
First of all, you actually give a little more credit to screening polygraph then the research supports. It is specific issue polygraph testing with consistant accuracy statistics in the mid 90s. Screening more consistently averages in the mid 80s. Now that would seem to make your question even more relevent except for one small point:
Anybody who has ever conducted or has been a consumer of background investigations understands the false negative rate (the rate in which disqualifying behavior was NOT revealed) is EXTREMELY high (somewhere in the 85% to 95% range). That means disqualifying behavior is not revealed 85-95% on the time! That makes background investigations only 5% to 15% accurate. In comparison, screening polygraph averages 85% accuracy. Now do you see why pre-employment polygraph testing is so prevelent?
How can background investigations be so inaccurate? Well, the posters on this site would have you believe that background investigators are lazy and incompetent and therefore rely on the poylgraph to do their jobs for them. Nothing could be further from the truth.
The reality is that unless some record is found that implicates the applicant in wrong doing of some kind (like an arrest record), or an ex-spouse/significant other, angry neighbor provides derogatory information, usually nothing but GLOWING reports come in on the candidate.
After all, how motivated would you be to crap all over your brother, sister, mother, or close army buddy when the background investigator knocks on your door? Besides, most people do not advertise that they have committed or are are currently involved in perpetrating felonous behavior. The polygraph goes right to the source of the information, the candidate him/herself. Most folks cannot successfully lie to themselves (People with that skill set generally go into politics).
Thanks again for your question and good luck in your future endevours.
Nonombre