Actual Innocence Research

The effects of “joinder” trials in jury decision making

In examining the case of David McCallum and William Stuckey, the author discusses the effects of a “joinder trial,” and calls for research on how such a structure may affect trial outcomes in ways that promote wrongful and rightful convictions.

By Kelsey Henderson, MA

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Almost all identified exonerations have occurred in cases in which the defendant was wrongly convicted at trial.1 Much of the innocence research has focused on specific factors or pieces of evidence – eyewitness misidentifications and false admissions, in particular – that lead to such errors of justice.  And while some scholars have tackled more fundamental issues involving the legal system (e.g., Vidmar & Coleman, 2014), social scientists have yet to examine the structure of the trial process itself in the context of wrongful convictions. Our topic this month does exactly that. In examining the case of David McCallum and William Stuckey, our author discusses the effects of a “joinder trial,” and calls for research on how such a structure may impact trial outcomes in ways that promote wrongful and rightful convictions.

Our guest-author this month is Kelsey Henderson. Kelsey is a PhD candidate at the University of Florida, where she also received her masters of arts in criminology & law. Her primary research interests are juror decision making, expert testimony and plea bargaining.

Case Overview 2

In Queens, New York on Oct. 20, 1985, two young black males forced Nathan Blenner into Blenner’s car and drove off. The car was located two days later in Brooklyn, after a security guard reported the car burned by a group of young men. Blenner’s body was found in Brooklyn’s Aberdeen Park, he had been shot once in the head.

Shortly after the murder, police questioned Terrence Hayward, who had a history of carjackings in the area. Hayward pointed detectives in the direction of William Stuckey and David McCallum, both 16 years old, claiming Stuckey possessed a gun that had been used to kill someone. Stuckey and McCallum were brought in for questioning a week after Blenner’s body was found. After hours of interrogation, Stuckey and McCallum both confessed to carjacking and killing Blenner. Both defendants quickly retracted their confession and pled not guilty, insisting they had confessed only because they were coerced and tricked into doing so. The videotaped confessions, lasting less than three minutes, contained numerous inconsistencies between the case evidence and the other suspect’s confession. In this case, the confessions had been videotaped, but not the interrogations leading up to that point. The crime and investigation was before the widespread use of forensic DNA testing. The confessions were the main evidence used to convict Stuckey and McCallum.

Stuckey and McCallum were tried before the same jury in adult criminal court, beginning in October 1986. After a six day trial, despite the lack of any evidence linking either defendant to the murder, they were found guilty and sentenced to 25 years to life. McCallum maintained his innocence since being convicted and had been denied parole repeatedly for failing to show remorse. According to McCallum, he refused to show remorse because he already fell for the false promise that admitting guilt would allow him to leave custody once before.

After years of writing to the district and assistant district attorneys, McCallum’s counsel made headway when newly appointed district attorney, Ken Thompson, and the Brooklyn Conviction Integrity Unit reviewed McCallum’s case. McCallum’s case also grabbed the attention of exoneree Rubin “Hurricane” Carter, who asked Thompson specifically to review the McCallum case. The CIU tested the DNA evidence found in Blenner’s car, which had not been originally tested. The DNA profile matched a convicted felon, and excluded Stuckey and McCallum. On Oct. 15, 2014, Thompson filed a motion to vacate the convictions of Stuckey and McCallum. McCallum was released immediately; Stuckey had passed away of a heart attack in prison in 2001. McCallum and Stuckey were officially exonerated in October 2014.

The “Joinder Effect”

One of the contributing factors of wrongful conviction in this case was the false confession of Stuckey and McCallum, typical of proven wrongful convictions ( However, I will focus on another potential cause, the joint trial structure of the Stuckey and McCallum trial. A joint trial, referred to as a “joinder” trial, is when one trial is held involving multiple plaintiffs or defendants associated with one case or when there are multiple charges against one defendant. The state may join multiple defendants under one trial if the defendants are alleged to have participated in the same transgression, or series of transgressions, constituting the offenses or offenses (Federal Rules of Civil-Appellate-Criminal Procedure, 1983). Thus, Stuckey and McCallum were eligible to be tried together for the multiple counts against them.     

When looking at a joinder of offenses, there are two competing interests at play: the time- and expense-saving nature of a combined trial versus the defendant’s right to a fair trial. In general, it is the trial judge’s decision to pursue or grant a joinder trial, however, the defense can file a pretrial motion for severance of charges if it is believed the joinder trial would be unduly prejudicial towards the defendant. If a defendant appeals based on the outcome of a joinder trial, he must show the judge abused his/her discretionary power in allowing the joinder trial. It is not enough to show that conviction would have been less likely if the trial structure had been different (United State v. Thomas, 1982); any evidence that would have been considered admissible at a severed trial, would be considered “harmless error” if allowed at the joinder trial (Georgetown, 1983). Judges are less likely to grant pretrial motions to sever the charges or grant separate trials for the defendants because of interests of judicial economy; reversal at the appellate level on the basis of a joinder mistrial is highly unlikely.

In the past, it has been noted that joinder trials can be prejudicial against the defendant. In U.S. v. Foutz (1976), the court stated that in a joinder trial the jury may confuse evidence across charges, evidence may build up over multiple charges, the jury may use evidence from one crime to infer criminality, the jury may cumulate evidence across all charges, and the defendant may be confounded in his attempt to refute multiple charges. The court also stated that in the case of a codefendant situation, joinder trials should not be permitted if either defendant’s strategy is antagonistic, for example, if both defendants assert their own innocence while blaming the other, or the jury cannot believe one defendant without disbelieving the other. In such circumstances, a joinder trial of codefendants would be not fair and is likely to violate both defendants’ rights to a fair trial (U.S. v. Foutz, 1976). In the Stuckey- McCallum case, a joinder trial was held with multiple defendants and multiple charges against each defendant.

Research has examined the effects of trial structure on jury decision making, often looking at outcomes in bifurcated trials (Greene, Woody, & Winter, 2000; Horowitz & Bordens, 1990; Horowitz & Sequin, 1986). Less empirical research has been devoted to the effects of joinder trials on jury decision-making. Of the research that has been conducted, the majority has examined the effects of combining multiple offenses of the same offender in one trial (Horowitz, Bordens, & Feldman, 1980; Tanford, 1985; Tanford, Penrod, & Collins, 1985). Less empirical focus has been on examining the potential biasing effects of trying two defendants in one trial, although one could understand what may happen based on those studies examining joined charges. This experimental research suggests juries are more biased against the defendant in a joinder trial versus a trial with a single charge (Horowitz, Bordens, & Feldman, 1980; Tanford, 1985; Tanford, Penrod, & Collins, 1985). Mock jurors are more likely to convict on a particular charge in a joinder trial with multiple charges than in a trial on the same single charge (Tanford, Penrod, & Collins, 1985). Further, judicial instructions about the biasing effects of a joinder trial have been found to be ineffective in reducing these effects (Tanford, 1985). Also, a joinder trial may lead mock jurors to be confused about the evidence (Tanford, 1985). Research also suggests that the increased conviction rate in joinder trial conditions is mediated by assumptions of the defendant’s criminality (Tanford, 1985). Other research supports this finding and suggests that a joinder trial leads to poorer ratings of the defendant compared to a trial with a single charge, and those ratings were related to mock jurors’ guilty decisions (Tanford & Penrod, 1982).

Following this research, Tanford and Penrod (1984) proposed an explanatory model to account for their findings, using three theories (sources) of prejudice: confusion, accumulation, and criminal inference. Using this model and results from their study, they suggest that a joinder trial fosters negative views of the defendant that influences jurors’ memories of evidence (confusing evidence amongst charges), perceptions of the evidence, and inferences about the sources of the defendant’s behavior based on his perceived criminal character. This leads jurors to build a strong impression of the defendant, which is more resistant to a/the judge’s instructions, and ultimately to be more conviction-prone in joinder trials. This negative impression is likely to also affect joinder trials with multiple defendants, in which jurors are likely to use one conviction to suppose the other and evidence from one case to infer guilt in the other. Overall, research on the effects of joinder trials suggests that they may be overly prejudicial towards the defendant, potentially yield an unfair trial, and result in a more conviction-prone jury (Bordens, & Horowitz, 1983; Greene & Loftus, 1985).

A crucial point to note is that the above-mentioned research focused on the effects of a joinder trial with one defendant and multiple offenses. A topic that has not been the focus of much empirical research is the potential biasing effects of a joinder trial with multiple defendants (co-defendants). In the Stuckey- McCallum case, the fact that both were tried together for multiple charges was likely a contributing factor to their wrongful conviction.

Research Ideas

As mentioned, research has generally focused on the effects of trial structure on juror decision making (i.e., bifurcated civil trials, bifurcated death penalty cases, joinder trials of one defendant and multiple offenses). In the future, researchers should examine the potential effects of joinder trials with multiple defendants and multiple charges; this research could investigate charge similarity, evidence similarity between offenses, and differences in verdicts between offenders if trial structure differed (separate versus joinder).

Another potential avenue for future research would be to investigate more closely jurors’ ability to notice variations in evidence that might alert them to the quality of that evidence in joinder trials (one defendant, multiple charges; multiple defendants) versus non-joinder trials. Are there differences, based on the trial structure, in jurors’ ability to evaluate evidence? Whether defendants are guilty or innocent of the charges (with evidence indicating as such) to determine if jurors can be sensitive to this when trials are and are not joined?


Amongst the other potential contributing factors to their wrongful convictions, the David McCallum and William Stuckey case highlights what the research findings demonstrate: joinder trials can be unduly prejudicial against the defendant. However, experimental research is needed to further investigate these processes and how they might contribute to rightful and wrongful outcomes in cases involving co-defendants. 


  1. According to the National Registry of Exonerations, only 11 percent of exonerees pled guilty. See website.
  2. Information about the case was gathered from the National Registry of Exonerations website and the Innocence Project website.


Bordens, K. S., & Horowitz, I. A. (1983). Information processing in joined and severed trials. Journal of Applied Social Psychology, 13, 351-370.

Federal Rules of Civil-Appellate-Criminal Procedure-West Law School Edition (1983). St. Paul, MN: West Publishing Company.

Georgetown Law Journal Staff. (1983). Project: thirteenth annual review of criminal procedure: The United States Supreme Court and Courts of Appeals. Georgetown Law Review, 72, 413-422.

Greene, E. & Loftus, E. (1985). When crimes are joined at Trial. Law and Human Behavior9(2), 193-207.

Greene, E., Woody, W.D., & Winter, R. (2000). Compensating plaintiffs and punishing defendants: Is bifurcation necessary? Law and Human Behavior, 24, 187-205.

Horowitz, I. A., & Bordens, K. S. (1990). An experimental investigation of procedural issues in complex tort trials. Law and Human Behavior, 14, 269-285.

Horowitz, A., Bordens, K. S., & Feldman, M. S. (1980). A comparison of verdicts obtained in severed and joined criminal trials. Journal of Applied Social Psychology, 10, 444-456.

Horowitz, I. A., & Seguin, D. G. (1986). The effects of bifurcation and death qualification on assignment of penalty in capital crimes. Journal of Applied Social Psychology, 16, 165- 185. Retrieved Oct. 25, 2014.

Tanford, S. (1985). Decision-making processes in joined criminal trials. Criminal Justice and  Behavior, 12, 267-385.

Tanford, S, & Penrod, S. (1982). Biases in trials involving defendants charged with multiple offenses. Journal of Applied Social Psychology, 12, 453-480.

Tanford, S., & Penrod, S. (1984). Social inference process in juror judgments of multiple offense trials. Journal of Personality and Social Psychology, 27(4), 749-765.

Tanford, S., Penrod, S., & Collins, R. (1985). Decision making in joined criminal trials: The influence of charge similarity, evidence similarity and limiting instructions, Law and Human Behavior, 9, 319-337.

Vidmar, N. & Coleman, J. E. (2014). The American adversary system: Sources of error in the criminal adjudication process. In A. D. Redlich, J. R. Acker, R. J. Norris, & C. L. Bonventre (Eds.), Examining wrongful convictions: Stepping back, moving forward (pp. 141-156). Durham, NC: Carolina Academic Press.

United States v. Thomas, 676 F 2s 239, 243 (7th Cir, 1982).