Further redirect examination of William Shields

📄 Further redirect examination of William Shields — Thursday, June 22, 1995

Address:

C:\DEPT103\CRIMINAL\1995\JUN\22\FURTHER-REDIRECT-EXAMINATION-O.DOC

TRIAL

▲ Day 101 of 167

◀ Recross-examination of William Shields Motion: DNA statistical evidence ▶

Witness: Dr. William Shields
Examiner: William Thompson
Called by: Defense • Date: Thursday, June 22, 1995 • Utterances: 12

In a brief further redirect examination, prosecutor Thompson gets DNA expert Dr. William Shields to confirm that British statistician Dr. Ian Evett — whose methodology defense expert Dr. Weir had relied on — advocates communicating DNA likelihood ratios to juries using descriptive words rather than raw numbers. Judge Ito, curious about the point, asks Shields directly how such evidence would be presented instead of as a number, and Shields explains Evett's verbal scale.

# 1 MR. THOMPSON:

One question.

# 2 THE COURT:

Sure.

FURTHER REDIRECT EXAMINATION BY MR. THOMPSON

# 3 MR. THOMPSON:

Now, Dr. Weir said his approach was based on an article by ion Evett, who is a British statistician and forensic scientist?

# 4 DR. SHIELDS:

That's correct.

# 5 MR. THOMPSON:

Do you know whether Dr. Evett advocates the use of likelihood ratios to communicate with juries or not?

KEY QUOTE

# 6 DR. SHIELDS:

He does.

# 7 MR. THOMPSON:

Does he advocate presenting likelihood ratios as numbers?

# 8 DR. SHIELDS:

No.

# 9 MR. THOMPSON:

Okay. Thank you.

# 10 THE COURT:

Well, if you're not going to do it as a number, how are you going to do it?

KEY QUOTE

# 11 DR. SHIELDS:

He uses words like "Strong evidence, extremely strong evidence, mild evidence, bad evidence."

KEY QUOTE

# 12 THE COURT:

All right. Thank you. Any other witnesses, Mr. Thompson?

Temperature

procedural

Key Quotes (3)

William Thompson

Do you know whether Dr. Evett advocates the use of likelihood ratios to communicate with juries or not?

Frames the methodological question of whether DNA statistical strength should be given to juries as numbers or as descriptive categories.

Lance A. Ito

Well, if you're not going to do it as a number, how are you going to do it?

The judge personally probes the alternative methodology, showing the court's own interest in how DNA evidence should be explained to a jury.

Dr. William Shields

He uses words like "Strong evidence, extremely strong evidence, mild evidence, bad evidence."

Describes Evett's verbal likelihood-ratio scale as the alternative to numeric presentation of DNA statistics to a jury.

Evidence (1)

Informal

Article by British statistician Dr. Ian Evett on methodology for presenting DNA likelihood ratios to juries, which defense expert Dr. Weir had relied on

discussed

Notable Exchanges (1)

Lance A. Ito•William Shields

After Thompson finishes his brief redirect, Ito himself asks Shields to clarify how DNA evidence strength would be conveyed to jurors if not expressed as a number, prompting Shields to describe Evett's verbal scale.

strategic

Objections

None recorded

Proceeding 6520 • 12 utterances • Defense witness

Criminal Trial

Department 103