📄 Re-redirect examination of Dr. Renee Shields — Thursday, June 22, 1995
Address:
C:\DEPT103\CRIMINAL\1995\JUN\22\RE-REDIRECT-EXAMINATION-OF-DR-.DOC
TRIAL
▲ Day 101 of 167

Re-redirect examination of Dr. Renee Shields

Witness: Dr. Renee Shields
Examiner: George Clarke
Called by: Prosecution • Date: Thursday, June 22, 1995 • Utterances: 14
George Clarke conducted a brief recross-examination of Dr. Shields on the topic of DNA mixture statistics. Clarke got Dr. Shields to concede that the UK methodology described by Dr. Weir—including likelihood ratios and Bayesian analysis—actually incorporates the known types of individuals involved in a case, whereas the simpler 'one in 71' frequency statistic Weir offered does not. Clarke's implicit point: Weir's method was more conservative and favorable to the defense than the more sophisticated techniques would have been.
1 MR. CLARKE:

Just a moment if I might, your Honor.

2 (Discussion held off the record between the Deputy District Attorneys.)
3 MR. CLARKE:

Just briefly, your Honor.

4 THE COURT:

Briefly.

RECROSS-EXAMINATION BY MR. CLARKE

5 MR. CLARKE:

Dr. Shields, with regard to mixtures, are you aware of whether or not mixture calculations are made by the methods described by Dr. Weir in the United Kingdom?

6 DR. SHIELDS:

I believe they are.

7 MR. CLARKE:

And that actually includes likelihood ratios; does it not?

8 DR. SHIELDS:

It does. They go so far as to go all the way to a bayesian analysis.

KEY QUOTE
9 MR. CLARKE:

And likelihood ratios even incorporate the known types of the individuals involved in the case, don't they?

10 DR. SHIELDS:

Yes.

11 MR. CLARKE:

Dr. Weir's offered frequencies such as the one in 71 that we discussed don't even incorporate the known types of the individuals who may be associated with the case, do they?

KEY QUOTE
12 DR. SHIELDS:

That's correct.

13 MR. CLARKE:

Thank you.

14 MR. CLARKE:

Nothing further, your Honor.

Temperature

procedural

Key Quotes (2)

Dr. Renee Shields
They go so far as to go all the way to a bayesian analysis.
Shields confirms that the UK's advanced methodology uses Bayesian analysis, which Clarke uses to show that Weir's simpler frequency estimate understated the strength of the DNA evidence against the defendant.
George Clarke
Dr. Weir's offered frequencies such as the one in 71 that we discussed don't even incorporate the known types of the individuals who may be associated with the case, do they?
The crux of the recross — Clarke establishes that Weir's 'one in 71' figure was a conservative floor, not an inflated number, undermining any defense suggestion that Weir overstated his statistics.

Evidence (1)

Informal
Dr. Weir's 'one in 71' DNA mixture frequency calculation discussed in prior testimony
discussed

Notable Exchanges (1)

George ClarkeDr. Renee Shields
Clarke walked Shields through a concession that likelihood ratios and Bayesian methods — which Shields had implicitly elevated as more rigorous — would incorporate known individual types and thus yield an even more incriminating result than Weir's conservative frequency estimate.
strategic

Objections

None recorded
Proceeding 6519 • 14 utterances • Prosecution witness
Criminal Trial
Department 103
⚖️ Start
📂 JUN 22, 1995 📄 Re-redirect examination of Dr.
JUN 22, 1995 KRT DvH TD