When a defendant stands trial, they are supposedly judged by a jury of their peers. But does the demographic makeup of that jury influence the final verdict? In your Criminological Psychology option, Bradbury and Williams (2013) is your key contemporary study investigating how race affects jury decision-making.

---

What you'll learn

• How researchers use real-world court data (archival research) to study jury decision-making.
• The specific effects of Black, White, and Hispanic juror representation on conviction rates of Black defendants.
• How to critically evaluate the study's high ecological validity against its correlational limitations (AO3).

---

The Background: Why Study Jury Race?

In many judicial systems, including those of the US and the UK, juries are expected to be impartial. However, social psychological theories of prejudice—such as Social Identity Theory (Tajfel & Turner, 1979)—suggest that we naturally favor our "in-group" (those we share characteristics with) and hold biases against the "out-group."

Historically, most research on jury bias relied on mock trials, where university students read written transcripts of a crime and voted on a hypothetical verdict.

Bradbury and Williams wanted to address this major limitation. They bypassed simulated courtrooms and analyzed real, completed trials to see if racial bias occurs when real lives and freedoms are on the line.

---

Aim and Methodology

The primary aim of Bradbury and Williams (2013) was to investigate whether the racial composition of a jury influences the likelihood of conviction for Black defendants.

Research Design

The researchers used an archival research design.

Instead of running an experiment, the researchers analyzed data from 360 real criminal trials involving Black defendants across four US jurisdictions (New York, Arizona, Washington D.C., and California).

The Variables

• Independent Variables (IVs): The racial composition of the juries. This was measured as the percentage of White, Black, and Hispanic jurors on each panel.
• Dependent Variable (DV): The final verdict of the trial (whether the Black defendant was convicted or acquitted).
• Control Variables (Covariates): To ensure that jury race was the actual factor influencing the verdict, the researchers statistically controlled for other key influences, including:
  • The strength of the prosecution's evidence (e.g., eyewitnesses, physical evidence).
  • The severity/type of the crime.
  • The type of legal representation (private attorney vs. public defender).

The relationship between these variables is mapped out below:

---

Key Findings

The researchers used advanced statistical modeling to isolate the effect of race. Their findings revealed clear, significant patterns of racial bias:

• White Juror Representation: Juries with higher percentages of White jurors were significantly more likely to convict Black defendants.
• Hispanic Juror Representation: Juries with higher percentages of Hispanic jurors were also significantly more likely to convict Black defendants.
• Black Juror Representation: Juries with higher percentages of Black jurors were significantly less likely to convict Black defendants.

---

Worked Example: Interpreting Statistical Significance

In research methods, we must determine if a pattern in our data is a genuine effect or just down to random chance. Because Bradbury and Williams analysed categorical data (e.g., jury composition category vs. guilty/not guilty verdict), a Chi-Square (${\chi }^2$) test of association is typically used to analyze these relationships.

---

Evaluation (AO3)

To score highly on 8- and 12-mark essay questions, you must balanced your AO1 description with rigorous AO3 evaluation. Let's break down the strengths and weaknesses of Bradbury and Williams (2013).

Strengths

• High Ecological Validity: Because the data came from real trials with real defendants, the study avoids the artificiality of mock-trial experiments. The decisions had life-altering consequences, meaning the data reflects genuine human behavior in a high-stakes environment.
• Robust Controls (Internal Validity): By statistically controlling for "covariates" like the strength of the evidence and the type of crime, Bradbury and Williams isolated race as the key variable. This reduces the risk that the results were simply due to Black defendants facing stronger evidence in certain trials.
• Ethical Soundness: The researchers used public archival court records. They did not actively deceive, stress, or manipulate participants, making it highly ethical under the BPS guidelines.

Weaknesses

• Correlational Nature (No Direct Causation): Archival research is fundamentally correlational. Although the researchers controlled for several variables, they could not control for everything (e.g., the charisma of the lawyers, the non-verbal behavior of the defendant, or individual juror prejudices). Therefore, we cannot establish a definitive cause-and-effect relationship.
• Geographical Generalizability: The sample was drawn from only four US jurisdictions. Legal procedures, jury selection rules (such as voir dire), and regional racial dynamics differ widely across the US, and differ even more from the UK legal system. Thus, the findings may not apply globally.

---

---