Criminological psychology (option) contemporary study: Bradbury and Williams (2013)

Aim and data

Aim: to find out whether the racial make-up of a jury affects its decisions. Predictions: Black defendants would be more likely to be convicted by juries with more White jurors, and by juries with more Hispanic jurors.

Data: secondary data originally collected by another research team studying real hung-jury cases in non-capital felony trials in four US jurisdictions: Maricopa County (Arizona), Los Angeles (California), the Bronx (New York) and Washington, D.C., in 2000 and 2001. Only trials with Black defendants were selected (about 60% of all defendants in these jurisdictions). Data included charges, jury decisions, demographics of defendants and victims, jury selection, evidence and deliberations.

Variables

• Dependent variable: conviction or not (conviction on any charge, including a lesser one, counted as conviction; acquittals and hung juries counted as no conviction).
• Independent variable: jury racial make-up, as the percentage of Black, White and Hispanic jurors.
• Controlled variables: strength of the prosecution case (amount of evidence and number of witnesses) and case type (violent and property crimes compared with drug crimes).

Results and conclusions

• Juries with a higher percentage of White jurors were more likely to convict Black defendants.
• Juries with a higher percentage of Hispanic jurors were also more likely to convict Black defendants.
• Juries were less likely to convict Black defendants of violent crimes than of drug crimes, and (marginally) less likely for property crimes than drug crimes.

Conclusions: jury composition matters. The authors suggested in-group/out-group bias may influence jurors; defence lawyers might improve acquittal chances by seeking Black jurors; juries should represent their communities; and the consistent tendency to convict Black defendants of drug crimes raises questions about how the system treats drug offences.

Evaluation

• Strengths: real verdicts in real trials give high ecological validity and credibility; large data set across four jurisdictions; the strength of evidence was controlled statistically.
• Weaknesses: secondary data collected for another purpose, so the researchers could not choose what was measured; correlational, so other differences between cases may explain the results (cause cannot be proven); only Black defendants and only US data in 2000 and 2001 (limited generalisability to other groups, countries and times); only hung-jury and convicting cases were in the original sample; the reasons behind jurors' decisions were not directly measured. The topic is socially sensitive.

Worked example

Why did Bradbury and Williams use secondary data, and what problem does this create?

1. Real jury deliberations cannot be manipulated or observed, so existing records of real trials were the only way to study real verdicts.
2. But the data were collected for another study, so the researchers could not control which variables were recorded, and they could not randomly assign jurors, so the findings are correlational.

Answer: Access to real verdicts, at the cost of control.

Check yourself

1. What kind of data did Bradbury and Williams (2013) use?
   • Primary data from a mock jury experiment
   • Questionnaires given to students
   • Observations of a single trial
   • Secondary data from real trials
   Show answer

   Secondary data from real trials. The data were collected by another research team.

2. What was the dependent variable?
   • The percentage of White jurors
   • Whether the defendant was convicted
   • The type of crime
   • The strength of the evidence
   Show answer

   Whether the defendant was convicted. Conviction or not.

3. What did Bradbury and Williams find?
   • Juries with more Hispanic jurors were less likely to convict Black defendants
   • Jury race made no difference
   • Black defendants were more likely to be convicted of violent crimes than drug crimes
   • Juries with more White jurors were more likely to convict Black defendants
   Show answer

   Juries with more White jurors were more likely to convict Black defendants. Higher percentages of White (and Hispanic) jurors increased convictions.

4. In how many different years were the trials in Bradbury and Williams held?
   Show answer

   2. 2000 and 2001.

5. Which variable did they control for?
   • The defendant's attractiveness
   • Pre-trial publicity
   • The strength of the prosecution's case
   • The judge's gender
   Show answer

   The strength of the prosecution's case. Amount of evidence and witnesses.

6. Explain one strength of Bradbury and Williams (2013).
   Show answer

   It used real jury verdicts from real trials rather than a mock jury, so it has high ecological validity and the findings apply to real courts.. Real data and why that matters.

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Sources

• Pearson Edexcel International Advanced Subsidiary/Advanced Level in Psychology specification, Issue 6 (November 2024, first assessment January 2026)
• Pearson IAL Psychology summary of studies: WPS03

Last updated 8 November 2026. Spotted a mistake? Tell us.