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LEPET base rate question

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Author Topic: LEPET base rate question
rnelson
Member
posted 01-07-2008 10:08 AM Click Here to See the Profile for rnelson Click Here to Email rnelson Edit/Delete Message
For Barry or anyone else.

Does anyone have any information about base-rates for admissions of problem behaviors pertaining to LEPET investigation targets and pretesting interview issues?

r

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"Gentlemen, you can't fight in here. This is the war room."
--(Stanley Kubrick/Peter Sellers - Dr. Strangelove, 1964)

[This message has been edited by rnelson (edited 01-07-2008).]

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Barry C
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posted 01-07-2008 11:37 AM Click Here to See the Profile for Barry C Click Here to Email Barry C Edit/Delete Message
Bud Rudacille did a study recently, and Mark Handler has a copy of a draft. I'd start there. Then, we have the drug survey I did.

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rnelson
Member
posted 01-07-2008 12:00 PM Click Here to See the Profile for rnelson Click Here to Email rnelson Edit/Delete Message
Thanks Barry,

I'll contact Mark.

I think your drug survey had a base rate around 50 percent, but I couldn't find it quickly in the old posts.

The quoted part below is from an old post regarding the DoDPI LEPET

quote:
1I Before (date), did you where shoes?

2SR Regarding your past, do you intend to answer each of my quesitons truthfully?

3C Are you the type of person who would lie to cover for someone?

4R Have you ever committed any serous crime?

5C Are you the kind of person who would betray a member of your family?

6I Before (date) did you ever drive a car?

7R Are you intentionally withholding and information about your involvement with illegal drugs?

8C Are you the type of person who would lie to stay out of trouble?

9R Are you intentionally falsifying or omitting any information on your applicaton forms?

10C Are you the type of person who would blamed someone else for something you did?

11R Have you committed more thefts that what you have told me?

C12 Would you lie to a supervisor for any reason, to save your job?


Are these common targets?

Also, does anyone have any anecdotal impressions about base rates for these types of targets? I know we have little data, so a range of impressions is interesting.

r

------------------

"Gentlemen, you can't fight in here. This is the war room."
--(Stanley Kubrick/Peter Sellers - Dr. Strangelove, 1964)

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rnelson
Member
posted 01-07-2008 12:37 PM Click Here to See the Profile for rnelson Click Here to Email rnelson Edit/Delete Message
Thanks Barry.

I'm sending you a monte-carlo simulation of a 4 question MGQT technique. I ran it with 10,000 iterations of 4 questions each, using base-rates of .1 for each question.

The monte-carlo simulation will use random numbers to generate truthful and deceptive spots, according to the specified base-rates, and then use more random numbers to produce question by question scores simulating 3-position point totals for each spot, by standardizing a random number to the mean and distribution of parameter estimates for deceptive and truthful spots which were derived from a bootstrap resample of the single issue cases in the OSS-3 training sample, after transforming the OSS-3 model to score the Kircher features in a nonparametric cumulative model according to the bigger-is-better rule. (breathe)

More later.


r


simulation will usin

seed variables for the monte-carlo are derived from the

------------------

"Gentlemen, you can't fight in here. This is the war room."
--(Stanley Kubrick/Peter Sellers - Dr. Strangelove, 1964)

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blalock
Member
posted 01-07-2008 12:40 PM Click Here to See the Profile for blalock Click Here to Email blalock Edit/Delete Message
Ray et al,

I am currently gathering data about base-rates for admissions on several problem behavior areas in the arena of law enforcement pre-emplyment testing. I have data on almost 70 applicants so far. The areas are as follows:

Employment History
Fired
Disciplined
Withholding Jobs
Undetected Violations

Illegal Drugs
# of Times Used
Types Used
Recency of Use
Sale
Transportation/Smuggling
Cultivation
Manufacturing
Recreational Use of Prescriptions

Detention
# of Times Arrested
# of Times Detained

Undetected Crimes
Theft
Murder
Assault/Battery
Vandalism
Sex
Fraud
Trespassing

I don't have the data calculated yet... How much data should I collect before I publish my findings?

Ben

[This message has been edited by blalock (edited 01-07-2008).]

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rnelson
Member
posted 01-07-2008 08:16 PM Click Here to See the Profile for rnelson Click Here to Email rnelson Edit/Delete Message
Ben,

That should prove very interesting.

With N=70 you may have enough to gain some preliminary figures that might begin to better inform further investigation efforts.

We are really at the onset stages of understanding base-rates and their contribution to LE officer hiring/training success.

Do you collect information about alcohol related problems? Also, how about gambling problems.

It would be interesting to see a literature search regarding the salient content for background investigation of LE candidates.

It would also be interesting to find cohorts of intermediate (3 to 8 years?) and long term LE officers (10+ years?), and perhaps even training failures and integrity failures to better evaluate the contribution of each data point to outcomes.

----------------------

Some estimates.

Observed rates of passing and failure, in mixed issues (independent RQs) exams will be subject to the multiplication rule for independent probability events. This means that we multiply the inverse of the base-rate of each of the RQs. For convenience, we'll assume the RQs to have equivalent base-rates, though this may not be the case in field situations.

Example 1: High base-rate. Assuming a LEPET exam with 4 RQs of BR = 50% = (1-.5)*(1-.5)*(1-.5)*(1-.5) = .0625 chance that any particular subject is being truthful to all RQs.

Example 2: Moderate base-rate. We'll use 15% and 3 RQs. = (1-.15)*(1-.15)*(1-.15) = 61.4% chance that any examinee is truthful to three questions of moderate BR.

Example 3: Low base-rate. Use 5% (.05) and 2 RQs. = (1-.05)*(1-.05) = 90.5% of examinee's can be expected to be truthful to two low BR questions.

Example 4: Very-low base-rate. 1% (.01) with 2 RQs = (1-.01)*(1-.01) = .98 or

The point is that if we are selecting targets that are salient or relevant to the task of predicting risk or future failure, we should be seeking higher BR behaviors that are correlated with the criterion. The trade-off is that we will find comparatively fewer and fewer persons who are being truthful to all questions.

Last week Donna posted some numbers at anti, regarding LEPET exams. I believe she indicated that approximately 70 percent of her subjects had passed. Assuming that LE applicants are not serious criminals (= moderate base-rates) and three to four questions, that would be about the right ball-park for passing rates.

r

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"Gentlemen, you can't fight in here. This is the war room."
--(Stanley Kubrick/Peter Sellers - Dr. Strangelove, 1964)

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Taylor
Member
posted 01-07-2008 09:05 PM Click Here to See the Profile for Taylor Click Here to Email Taylor Edit/Delete Message
I run an LEAT not a LEPET test. 4RQ's on armored car companies and 5 RQs on LE. One thing I didn't list over there is the ones that passed may have made damaging admissions in the pretest and will not be hired. One of the minons wanted to know how many of the 70% used CM's....I didn't even reply. They will slant anything over there.

Today I tested 5 for an armored car company (long day!). First one only slept 15 min in the past 27 hours (plus I think he is an illegal and admitted to some drugs and I know I would have got more if I proceeded - I declined to test him). The second passed and will be hired. The third has used drugs in the past two years - disqualified. The fourth denied researching polys but used CMs and kept smiling...(I am sure I will have my name in mud at AP sometime soon)-plus he sold drugs - another disqualifier. The fifth was a LIAR. So today I only had 1 out of 5.....bad day.

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blalock
Member
posted 01-08-2008 08:56 AM Click Here to See the Profile for blalock Click Here to Email blalock Edit/Delete Message
Ray,

In answer to your question, I do collect information about alcohol and gambling-related problems. It will not be shown in the study that I am currently working on since neither our application nor pre-screen currently do not cover those issues, but the information is collected at the polygraph phase, and I will have it for possible evaluation and study.

Ben

[This message has been edited by blalock (edited 01-08-2008).]

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