Objectives

The “shadow of the trial” (SOT) theory posits that plea decisions result from mathematical predictions of probability of conviction (POC) at trial and potential trial sentence (TS). Tests of the SOT model often find support in the aggregate, but not at the individual level. This study examines the factors that account for adherence to, or deviation from, the SOT model, such as mathematical competence, a factor not previously examined in tests of the SOT model.

Methods

Participants were randomly assigned to one of nine conditions corresponding to manipulations of probability of conviction (10%, 50%, 90%) and potential trial sentence (5, 15, 25 months). After reading a case description, participants were asked whether they would accept a plea offer and how much time in jail they would be willing to spend; a subset of participants was offered a counter plea offer. Participants then answered questions assessing numeracy and about their legal opinions and personal characteristics.

Results

Results showed that probability of conviction, but not trial sentence, influenced shadow model adherence. Participants assigned to 50% and 90% POC conditions were significantly less likely to deviate from the SOT model than participants assigned to 10% conditions. This effect did not interact with TS. Additionally, the odds of fitting the SOT model increased significantly as participants’ numeracy scores increased.

Conclusions

Our results raise questions about the validity of the SOT model at low POCs and challenge its assumption that defendants are capable of conducting the mathematical calculations required to fit the model.

中文翻译：

---

摆脱阴影：在“审判的阴影”中解释个人与辩诉交易的背离

目标

“审判的阴影”（SOT）理论认为，辩诉决定是由对审判和可能的审判句子（TS）的定罪概率（POC）的数学预测得出的。SOT模型的测试通常会在总体上找到支持，但不能在单个级别上提供支持。这项研究检查了影响遵守或偏离SOT模型的因素，例如数学能力，这是以前在SOT模型测试中未曾检查过的因素。

方法

参与者被随机分配到九种条件之一，分别对应于定罪概率（10％，50％，90％）和可能的审判期（5、15、25个月）的操纵。阅读完案例描述后，询问参与者是否愿意接受辩诉要约，以及他们愿意在监狱中度过多少时间；向部分参与者提供了反辩要约。然后，参与者回答了评估计算能力以及有关其法律意见和个人特征的问题。

结果

结果表明，定罪的概率（而不是审判语句）影响影子模型的依从性。与分配给10％条件的参与者相比，分配给50％和90％POC条件的参与者偏离SOT模型的可能性要小得多。该作用与TS不相互作用。此外，随着参与者的算术得分提高，拟合SOT模型的几率也大大提高。

结论

我们的结果提出了关于在低POC下SOT模型的有效性的疑问，并质疑其假设，即被告能够进行适合该模型的数学计算。