The Burdens of External Costs

Fun fact: I am on the UVA Mock Trial team.

We travel across the country competing against the best schools in the nation. Our trials can be about anything from bribery to copyright infringement to murder. In any given round, we represent attorneys and witnesses for the prosecution/plaintiff and the defense—using case facts to build legal arguments. Over the years, I've seen that in both civil and criminal trials, unanimity amongst jurors is required to find a defendant guilty. But what differs between civil and criminal trials is something called the burden of proof. Think of this as a measure of how certain a juror has to be of the defendant’s guilt. In criminal trials, the prosecution must prove the defendant is guilty beyond a reasonable doubt—meaning that jurors have to be absolutely certain of the defendant’s guilt in order to convict. But in civil cases, the burden is a preponderance of the evidence (more likely than not—51%). This burden directly effects how we construct our legal arguments.

But why are the burdens different? The disparity in the external costs are to blame. To ground this in the analysis we walked through in class, its helpful to think of the juror's decision making cost as a constant as the jurors aren’t being effected by the outcome.  But in this example instead of N_a* being the number of voters, it represents the certainty a juror has in the defendant’s guilt. The external cost curve varies between civil and criminal cases. The external costs of a guilty verdict in a criminal case are higher, meaning that the N­_a* is larger—just as it would be if we were ratifying a constitutional amendment. 

Think about it. The consequence of being found guilty for a crime is a jail time—a loss of someone’s liberty (and their right to vote #electionseason). Whereas the consequence of being found liable for a civil tort is (usually) a monetary cost. A loss of one’s freedom and the repercussions of being convicted of a crime are significantly higher than paying (even the largest of) fines. Money is something that can be regained over time—even prisoners are paid for labor. So in civil cases with lower external costs, N_a* doesn’t have to be maxed out. But one’s liberty is nearly, if not entirely suspended in prison. So, when making the decision to take someone’s freedom we want to make sure that jurors don’t have a semblance of doubt in the person’s guilt. Beyond a reasonable doubt doesn’t mean doubting reason—but it does call for certainty and a maximized N­_a*.