Prosecution expert gets cross-examined

I watched the defense cross-examine the prosecution expert in the Jodi Arias murder trial. I post this as a lesson in how a psychologist can be attacked in court.

The defense asked about a web page for Janeen DeMarte:

Qualifications

Years in Practice: 8 Years
School: Michigan State University
Year Graduated: 2009
License No. and State: 4120 Arizona

The apparent discrepency here is that she did not get her degree until 2009, and got her license in 2010, and yet she still claims to have practiced for 8 years. The simple answer is that she was a student practicing under the supervision of licensed psychologists.

Next the lawyer asked about Jodi scoring a PTSD diagnosis from the PDS test. DeMarte was accused of sharing the copyrighted PDS test questions with the prosecutor, even tho he is not a licensed psychologist and public distribution of the test could invalidate the test.

Here is the list of PDS questions, from an online Jodi Arias discussion:

Below is a list of traumatic events or situations. Please mark YES if you have experienced or witnessed the following events or mark NO if you have not had that experience.

1. Serious accident, fire or explosion ? Yes ? No
2. Natural disaster (tornado, flood, hurricane, major earthquake) ? Yes ? No
3. Non-sexual assault by someone you know (physically attacked/injured) ? Yes ? No
4. Non-sexual assault by a stranger ? Yes ? No
5. Sexual assault by a family member or someone you know ? Yes ? No
6. Sexual assault by a stranger ? Yes ? No
7. Military combat or a war zone ? Yes ? No
8. Sexual contact before you were age 18 with someone who was 5 or more years older than you ? Yes ? No
9. Imprisonment ? Yes ? No
10. Torture ? Yes ? No
11. Life-threatening illness ? Yes ? No
12. Other traumatic event ? Yes ? No

Actually these questions are from the closely related PTSD Symptom Scale (PSS), but the 12 items are essentially the same.

When Jodi did this test for the defense psychologist Samuels, she checked Yes for 1-4 and 12. For #12 she wrote "repeated emotional/psychological abuse". When asked on the PDS which of these was worst, she chose "4. Non-sexual assault by a stranger" and added, "assaulted and life threatened".

At the time that Jodi did the PDS test, she was claiming that strangers killed Travis and tried to kill her. She now admits that this story was a lie. Thus the PTSD diagnosis was based on a lie.

The defense got DeMarte to admit that assault by a non-stranger could also be traumatic.

There was also some discussion of the Trauma Symptom Inventory™-2 (TSI™-2) test. DeMarte used the previous TSI, and was criticized for not using the latest TSI-2 revision.

While DeMarte is younger and less experienced than Samuels and LaViolette, she had the advantage that she could answer a yes-no question with a yes or a no.

The copyright issue seems ridiculous. The defense lawyer put these questions up on the screen where they were shown on HLN TV. It is just a list of traumas. There are also a bunch of questions about how upsetting the trauma was, such as whether it causes nightmares. If someone wants to fake PTSD on the PDS test, it is pretty easy whether she has seen the test or not. Some of the other psychology tests are harder to fake. Probably the most secret thing about the PDS test is the minimum number of lies to tell to get a PTSD diagnosis. But that is essentially what Jodi did, so you could get a good idea by just watching the trial.

While copyright law does allow test-makers to charge money for their tests, public trials use public evidence. These test-makers market their tests for forensic work, so there is no avoiding the public learning how they are used for and against a murder defendant.

I don't think that the defense did much damage to this witness. Criticism about bias and credentials do not impress me much, and nitpicking about hours, scoring methods, and experience does not either. But that is mainly because I put very little stock in these experts' opinions anyway. To me, they are only convincing when they are explaining verifiable facts and textbook knowledge. Much of what they say is just crap. But I am a skeptic, and the jury is probably more gullible.