The document discusses jury selection strategies and game theory approaches. It presents examples of how to use game theory to determine optimal "challenge thresholds" for exercising peremptory challenges. Simulation studies show game theory strategies outperform alternatives like pool averages or coin tosses. While jury selection involves both art and science, game theory can mathematically determine optimal challenges once juror ratings are established. The goal is to maximize jury favorability through strategic use of challenges based on ratings, though real-world challenges require exercising them with incomplete information.

1. Jury Selection
Scenarios & Strategies
“…….almost every case has been won or lost when the jury is sworn.”
--Clarence Darrow. (1936)

2. Agenda:
• Discuss the exercise of peremptory challenges during
jury selection.
• Specifically, how to best use your peremptory
challenges to obtain the most favorable jury

3. “Experienced trial lawyers view jury selection as a highly tactical, yet always mysterious, exercise in which cases
are often won or lost.” David Hittner & Eric J.R. Nichols, Jury Selection in Federal Civil Litigation: General Procedures, New Rules, and the Arrival of Batson, 23 TEX.
TECH L. REV. 407, 409 (1992)
“Trial lawyers agree that the jury selection process is the single most important aspect of the trial proceedings. In
fact, once the last person on the jury is seated, the trial is essentially won or lost.” Margaret Covington, Jury Selection: Innovative
Approaches to Both Civil and Criminal Litigation, 16 ST. MARY’S L.J. 575, 575-76 (1984)
“Jury selection can be the most important phase of a trial. Pick the right jury and the battle is half won. But select
the wrong jury, and the case is lost before [the] evidence is even heard.” Chris F. Denove & Edward J. Imwinkelried, Jury Selection: An
Empirical Investigation of Demographic Bias, 19 AM. J. TRIAL ADVOC. 285, 285 (1995)
“The importance of jury consultants is increased by the widespread belief that a trial is often won or lost during
jury selection” Franklin Strier & Donna Shestowsky, Profiling the Profilers: A Study of the Trial Consulting Profession, Its Impact on Trial Justice and What, If Anything,
to Do About It, WIS. L.REV. 441, 443 (1999)
Some References on Jury Selection

4. Jury Selection – Two Step Process
1. Rate Jurors
• Psychological Profiling
• Demographic Surveys
• Mock Trials
• Social Media Profiling
• Jury Questionnaires
• Voir Dire
2. Exercise Challenges
• Struck
• Ordered Sequential
• Unordered Sequential
• Variations thereof

5. Rate
Jurors
Exercise
Challenges
Jury Selection – Two Step Process (cont’d)
• Step 1 - Evaluating & rating jurors: relies on
experience, intuition, ….. An art
• Step 2 – Exercise challenges: A mathematically
optimal solution based on Game Theory
• Steps 1 and 2 are of equal importance!

6. 0
20
40
60
80
100
120
1 2 3 4 5 6 7 8 9 10 11 12
Performance%
(Value/GameTheoryvalue)
Jury Size
Jury Value Simulation Study
Game Theory
Pool Average
Coin Toss
Always Accept
Assumptions:
Strike & Replace
4:4 Challenges
Fair Jury Pool [0,10]

7. The Problem:
• Given a set of juror and jury pool ratings…..
• If you challenge a juror, will the replacement be any better?
• If so, will the opposing party challenge the replacement leaving
you even worse off?
• Should you reserve your challenge for later in the process?

8. Example 1 – Ordered Strike and Replace
Juror 1
Jury seats: 1
Plaintiff perempts: 1
Defendant perempts: 1
Should you challenge Juror 1?
Juror 2 Juror 3
Jury Box Jury Pool
3 8 2

9. = Plaintiff decision point
= Defendant decision point
Example 1 - Game Theory Analysis:
Juror 1, r = 3
Juror 2, r =8
Juror 3, r = 2
Juror 2, r = 8
Juror 3, r =2
<r> = 2
<r> = 8
<r> = 3
Juror 1, r = 3

10. Example 1 – Ordered Strike and Replace
Juror 1
Jury seats: 1
Plaintiff perempts: 1
Defendant perempts: 1
Should you challenge Juror 1?
Juror 2 Juror 3
Jury Box Jury Pool
3 8 2
No!

11. Ordered Sequential System Jury seats: 6
Plaintiff perempts: 3
Defendant perempts: 3
Which jurors should you challenge?
Jury Box
Jury Pool
Juror 1
3
Juror 2
7
Juror 3
5
Juror 4
2
Juror 5
5
Juror 6
6
Juror 7
5
Juror 8
2
Juror 9
8
Juror 10
3
Juror 11
0
Juror 12
1

12. Jury
Seats
Plaintiff
Challenges
Defendant
Challenges
Decision
Points
1 1 1 4
4 2 2 1,122
6 3 3 51,417
8 4 4 2,554,482
12 4 4 30,339,708
Game Tree Complexity
• Computer is required for realistic situations

13. Example 2 – Unordered Strike and Replace
Juror 1
Jurors: 1
Plaintiff perempts: 1
Defendant perempts: 1
Jury Pool: [0,10]
• Should you challenge Juror 1?
• What is your “Challenge Threshold”? (pool average?, best guess?, coin toss?)
• How might this change if you had fewer/more peremptory challenge?
Juror 2 Juror 3
Jury Box Jury Pool
4 Pool average = 5

14. = Plaintiff decision point
= Defendant decision point
Example 2 - Game Theory Analysis:
Result: Challenge Threshold = 3.75
Juror 1
Juror 2,3
Juror 2,3
Juror 2,3
Juror 2,3
<r> = 6.75
<r> = 3.75
Juror 1

15. Example 2 – Unordered Strike and Replace
Juror 1
Jurors: 1
Plaintiff perempts: 1
Defendant perempts: 1
Jury Pool: [0,10]
• Should you challenge Juror 1?
• What is your “Challenge Threshold”? (pool average?, best guess?, coin toss?)
• How might this change if you had fewer/more preempts?
Juror 2 Juror 3
Jury Box Jury Pool
4 Pool average = 5
No!

16. Jury Value vs. Challenge Threshold
Assumptions:
Strike and Replace
1 seat jury
1 challenge per side
Uniform Pool: [0,10]
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9 10
JuryValue
Challenge Threshold

17. Jury Value vs. Challenge Threshold
Assumptions:
Strike and Replace
12 seat jury
1 challenge per side
Uniform Pool: [0,10]
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9 10
JuryValue
Challenge Threshold

18. Jury Value vs. Challenge Threshold
Assumptions:
Strike and Replace
12 seat jury
4 challenges per side
Uniform Pool: [0,10]
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9 10
JuryValue
Challenge Threshold

19. 0
1
2
3
4
5
6
7
1 2 3 4
PlaintiffChallengeThreshold
# of Plaintiff Challenges
1 seat, def. has 1 challenge
12 seats, def. has 4 challenges
Sample Results: Threshold Variation by Challenge Numbers:
Assumptions:
Uniform Pool: [0,10]

20. Key Results So Far:
• GT Challenge Thresholds can differ significantly from pool average
1.5 to 6.5 in above example (scale 0-10).
• GT Thresholds depend upon:
Selection system rules / # of challenges / # of jury seats / jury pool dist..
• Calculation of GT-thresholds in real-world cases requires computing power.
Once you have established your juror ratings…..
optimal peremptory challenges are mathematically determined.

21. How much difference GT make?
1. Juror Ratings
• Psychological Profiling
• Demographic Surveys
• Mock Trials
• Online Profiling
• Jury Questionaires
• Voir Dire
2. Peremptory Challenges
• Jury Science (Game Theory)
• Pool Average
• Coin Toss
• Always Accept
Skill, experience, practice…… an art. Mathematical strategy…… a science.

22. 0
20
40
60
80
100
120
1 2 3 4 5 6 7 8 9 10 11 12
Performance%
(Value/GameTheoryvalue)
Jury Size
Performance Against Game Theory
Game Theory
Pool Average
Coin Toss
Always Accept
Assumptions:
4:4 Challenges
Pool [0,10]
0
20
40
60
80
100
120
1 2 3 4 5 6 7 8 9 10 11 12
Performance%
(Value/GameTheoryvalue)
Jury Size
Performance Against Game Theory
Game Theory
Pool Average
Coin Toss
Always Accept

23. Jury Science Software – In the Courtroom (Windows Demo)

24. http://juryscience.us
Thank you!
Our product line:
Jury selection suite including GT-based selection recommendations
Jury Science Early Adopter Program:
http://juryscience.us
Available per-trial consultation

28. 0
20
40
60
80
100
120
1 2 3 4 5 6 7 8 9 10 11 12
Performance%
(Value/GameTheoryvalue)
Jury Size
Performance Against Game Theory
Game Theory
Pool Average
Coin Toss
Always Accept
Assumptions:
4:4 Challenges
Pool [0,10]
0
20
40
60
80
100
120
1 2 3 4 5 6 7 8 9 10 11 12
Performance%
(Value/GameTheoryvalue)
Jury Size
Performance Against Game Theory
Game Theory
Pool Average
Coin Toss
Always Accept
Game Theory 3:4

29. 1
2
3
4
1 2 3 4 5 6 7 8 9 10 11 12
PlaintiffChallengeThreshold
Jury Size
Sample Results: Threshold Variation by Jury Size
Assumptions:
1 challenge per side
Uniform Pool: [0,10]

30. “experts in the field believe that eighty-five percent of the cases litigated are won or lost when the jury is selected” Herald Price Fahringer, “Mirror, Mirror on the Wall . . . ”: Body Language, Intuition, and the Art of Jury Selection, 17 AM. J. TRIAL ADVOC.
197,197 (1993)
“Voir Dire is the most important, yet least understood portion of a jury trial.” Harvey Weitz, Voir Dire in Conservative Times, 23 LITIG. 15, 15(1996
‘the importance of jury consultants is increased by the widespread belief that a trial is often won or lost during jury selection’ Franklin Strier & Donna Shestowsky, Profiling the Profilers: A Study of the Trial Consulting Profession, Its Impact on Trial Justice and
What, If Anything, to Do About It, 1999 WIS. L.REV. 441, 443
“I begin with the premise that jury selection is the most significant stage of any trial.” Cf. Milstein v. Mut. Sec. Life Ins. Co., 705 So. 2d 639, 641 (Fla. Dist. Ct. App. 1998) (Sorondo, J., specially concurring)
“Experienced trial lawyers agree that a case can often be won or lost in voir dire.” 45 AM. JUR. Trials§ 144 (1992)
“Lawyers apparently do win, as they occasionally boast, some of their cases during, or with the help of voir dire.’ V. HALE STARR & MARK MCCORMICK, JURY SELECTION: ANATTORNEY’S GUIDE TO JURY LAW AND METHODS§ 3.8 (1985)
“Many attorneys believe that trials are frequently won or lost during [jury selection].” JON M. VAN DYKE, JURY SELECTION PROCEDURES: OUR UNCERTAINCOMMITMENT TO REPRESENTATIVE PANELS139 (1977)
“[a] case may be [won] or lost at the [jury selection stage]” Jeffery R. Boyll, Psychological, Cognitive, Personality and Interpersonal Factors in Jury Verdicts, 15 LAW & PSYCHOL. REV. 163, 176 (1991)
“[M]any skilled trial attorneys maintain that trials can be won or lost during the jury selection process.” Janeen Kerper, The Art and Ethics of Jury Selection,24 AM. J. TRIAL ADVOC. 1, 3 (2000)
“Many trial lawyers believe that a jury trial is won or lost at the jury selection phase.” Robert R. Salman & Suzanne A. Salman, Points to Ponder for Arbitration Agreements, 43 PRAC. LAW. 31, 34 (1997)
“Voir Dire is one of the most critical phases of the trial: all can be lost (if not necessarily won) at this point.” Leslie Snyder, Attorney Conducted Voir Dire in a Criminal Case, inTHE JURY 1984: TECHNIQUES FOR THE TRIAL LAWYER243, 246 (PLI Litig. & Admin.
Practice Course, Handbook Series No. 274, 1984)
“Many attorneys believe that a case can be won or lost during the jury selection stage of the trial.” Cheryl A. C. Brown, Comment, Challenging the Challenge: Twelve Years After Batson,Courts are Still Struggling to Fill in the Gaps Left by the Supreme Court, 28
U. BALT. L. REV. 379, 379 (1999)
“[M]any attorneys believe trials are frequently won or lost during jury selection.” Eric Wertheim, Note, Anonymous Juries, 54 FORDHAM L. REV. 981, 984 (1986)
“[a] few authors actually rate [voir dire as] the most important element in trial preparation” IRVIN OWEN, DEFENDING CRIMINAL CASES BEFORE JURIES: A COMMON SENSEAPPROACH92, 109 (1973)
“The examination of jurors on the voir dire is looked upon by the practitioner as a very critical period of the procedure, when the greatest circumspection and discrimination are to be exercised. Accordingly we find the process lengthened to a tedious and
exasperating extent in trials of great importance . . . . ” JOHN PROFATT, A TREATISE ON TRIAL BY JURY, INCLUDING QUESTIONSOF LAW AND FACT § 166 (San Francisco, Sumner Whitney & Co. 1877
“…because he or she realizes that he or she can put on the best play in the world, but without an audience that is receptive to the play, it will be misunderstood and not comprehended”) Cathy E. Bennet etal., How to Conduct a Meaningful & Effective Voir
Dire in Criminal Cases, 46 SMU L. REV. 659,680-81 (1992) (explaining that a good trial attorney puts the same amount of effort in selecting a jury as is put in presentation at trial)
“Skillfully conducted voir dire is the most important element in a fair trial.” Morris Dees, The Death of Voir Dire, 20 LITIG. 14, 14 (1993)

31. Art:
A skill, typically acquired through practice.
Science:
Knowledge based on fact.
but first… Is jury selection an Art or a Science?

32. • Game Theory (Jury Science)
• Pool Average
• Coin Toss
• Always Accept
Possible Strategies for
Determining Challenge Thresholds Include:

33. Key results:
 GT strategies win in simulation studies (approx. +1 challenge).
 GT thresholds depend upon:
Selection system rules / # of challenges / # of jury seats / juror ratings.
 Calculation of GT-thresholds in real-world cases requires computing power.
 Once you have established your juror ratings (the Art)…..
optimal peremptory challenges are mathematically determined (the Science) .

34. The Goal:
• To maximize the favorability of a seated jury.
By Applying:
• Strategic use of Peremptory Challenges.
Based Upon:
• Juror (and Jury Pool) Ratings.
However….
It is often the case that one must exercise a challenge with
incomplete information about subsequent jurors and the
potential actions of opposing parties.

35. 0 5 10
Jury Pool
Juror Challenge Accept
Plaintiff (desires highest ratings):
Would you exercise a challenge?
Why or why not?
What is your ‘Challenge Threshold’?
3.75
Scenario 1: (Unordered Sequential System)
Jury seats to fill: 1 Jury Pool: [0,10]
Plaintiff Challenges: 1 Pool Average: 5
Defendant Challenges: 1

36. Scenario 1 – Unordered Sequential System
2 3 4 4 5 5 5 5 5 8 8 8
Jurors: 12
Plaintiff perempts: 4
Defendant perempts: 4
Jury Pool: [0,10]
• Whom do you challenge?
• What is your “Challenge Threshold”? (pool average?, best guess?, coin toss?)
• How might this change if you had fewer/more preempts?