I am a software engineer trying to understand how judges make decisions in lawsuits. In computer and other sciences there is a concept of deterministic system:

In mathematics and physics, a deterministic system is a system in which no randomness is involved in the development of future states of the system. A deterministic model will thus always produce the same output from a given starting condition or initial state.

In lay terms this simply means that if the system is being fed the same input again and again it will generate exactly the same output each time.

If applied to legal system:

  1. Each judge would be a sub-system that builds the whole US legal system
  2. Evidence provided to the judge under lawsuit would be one kind of the input
  3. Ruling made by the judge would be the the output of the lawsuit
  4. Lawsuit would be a test to see how legal system reacts on particular input

Here are my questions (if you feel comfortable answering only some of these questions I would still appreciate it):

How deterministic is the US legal system? Can you provide examples of popular lawsuit instances that were almost the same but resulted in very different outcome?


If you are familiar with the steps that lawsuit has to go through in the US legal system, then what are these steps (e.g. assigning a random judge to a lawsuit; same judge unpredictably deciding what is and what isn't convincing evidence to him; same judge deciding how much of punishment to give for each violation under same circumstances ...). How much unpredictability does each step introduce and what is the typical source of that unpredictability?


What are efforts to make the legal system more deterministic (e.g., let computers to contribute to ruling, precedent-court ...)? Are persons involved in the judicial system concerned about this problem, and does it have a term in the legal world?

Also, I understand that this question is quite general and does not specify some of the variables that could affect answers (e.g. country or state, type of lawsuit). You can chose how to answer it.


How deterministic is the legal system? It depends. And less than we might wish.

It depends on the case. How complex is the fact pattern? How strong is the evidence? How clear is the law? How compelling are the legal precedents? Questions of that nature.

The only generalization I might make would be that "lower level" cases seem more deterministic than "higher level" cases. By higher level, I mean those heard by a supreme court making constitutional decisions.

Here is a web site that has created a prediction market out of supreme court cases. Many have written on this topic.

Read this answer. It is an excellent treatise on the subjectivity of the legal system. Written by a real attorney. Read this answer too.

My advice: If you seek a deterministic system, don't look to the legal one.

  • 3
    Not to mention how long it has been since the judge last ate: well fed judges are more compassionate.
    – Dale M
    Dec 12 '15 at 8:30
  • 1
    Lower courts are equally, if not more, random, than higher courts. It just doesn't make the papers as often.
    – ohwilleke
    Nov 21 '17 at 5:47

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.