The Worst Math Ever Used In Court

As math and our minds both become more sophisticated, we can use strategies like probability to fill gaps in the unknown. That’s particularly useful in a court of law, where we almost never have all the facts we need. But what happens when bad math makes an uncertain situation even worse? In this case, people go to prison. And all it took was the misapplication of the product rule.

By inventing a series of probabilities and pretending that they were independent, a Los Angeles prosecutor ruined the lives of Janet and Malcolm Collins. A complex situation involving bad witnesses, racism, and prosecutorial overreach was reduced to a simple multiplication problem that never, ever should’ve been a part of the trial.

If there’s an upside to this catastrophe, it’s that the California Supreme Court used an appeal to the Collins trial to eviscerate bad math in the courtroom and lay the foundation for more appropriate uses of math going forward. From its roots as a “veritable sorcerer” to processing what several newspapers called “Trial By Computer,” the Collins probability trial has extended over 50 years of influence on legal proceeding -- and we’re just getting started.

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Vsauce2:

Hosted and Produced by Kevin Lieber

Research and Writing by Matthew Tabor

Editing by John Swan

Huge Thanks To Paula Lieber

#education #vsauce #crime

[ShortHax]

Numbers don’t lie. People misusing numbers do

[bobh]

Take the judge in the case. Take the chances of having his first name, last name, college attended, wife’s name, number of children, and years as a judge and you can “prove” he does not exist because the probability is so small that all of those characteristics exist in one person!!!!

[rossjennings]

I am so disappointed in the math professor who was called as an expert witness. Assuming he really knew his stuff, he should have seen this abuse of the product rule coming from a mile away, and it was his responsibility to point it out.

[Talsar]

love how, had they been guilty, the accomplice got more jail time than the person who actually carried out the assault and robbery.

[pbs]

This actually falls into a larger category, which is prosecutors and lawyers exploiting other peoples' ignorance (jurors, etc.).
It can be a bluff (the prosecutor was spewing math knowledge he knew he didn't understand himself and could be incorrect), or they're convinced they know what they're talking about and that whoever they're trying to convince knows less than them.

[Arceaus]

One thing that I also felt wasn't really touched on in the refuting arguments:

"At the end of the alleyway, a man named John Bass witnessed a white blonde woman with a ponytail get into a yellow car, and drive past him. He saw that the driver was a black man with a beard and a mustache." That was the description given about the two people. The entire probabilistic argument presented was heavily based on the probability of a _couple_ matching those six requirements. *Where in the accusing descriptions does proof come up that the two people in John Bass' view were even a couple to start? If we assume John saw the two correct people, he saw the robber and her getaway driver. That does not make a couple.*

I feel that was incredibly glossed over in the courtroom, almost more so than anything else.

[MrMaster]

I love how the court's references for how they arrived to the 40% probability was citing literal intro to probability books

[ucantSQ]

Where was the defense on cross-examination!? You've gotta be a terrible lawyer to let this testimony fly. "No questions, your honor. I'd rather be fishing."

[rockerrock]

Prosecutors should face ramifications if they are solely responsible for a wrongful conviction.
Especially if it is the result of fabricating evidence, and just making up probabilities is essentially fabricating evidence.

[WooperSlim]

6:58 - Another way to think about it, the 1 in 12 million they calculated is supposedly the probability a random person met all those characteristics. But police weren't arresting random couples, but specifically those that match the description. That's why the probability that they are innocent is so much higher, because it isn't out of all couples, but out of all others that match that description.

[crownedprince]

I love how interesting this can get and how you are pretty much an information page but its simplified but not overly simplified so it can be enjoyable as well as the music and the mood set in each section

[xl]

They forgot to consider "probability that she didn't remember correctly", or "probability that she made up her testimony"

[LOLonHere]

"Things needs to be really dumb, before we get smart"
Wise words, that's why no matter what anyone says, you're not useless.

[EpicBoss-]

When the people trying to prove that a minecraft speedrunner was or was not cheating are better at using probabilities than actual criminal prosecutors, you realize how awful our legal system is

[dxf]

seems like a harsh sentence for purse snatching in any case.

[MrKhaosBlaze]

Probably the worst timing to use Betty White for the victim.

[warfjm]

Prosecutors wanting a win just to win is a miscarriage of justice. Their duty is to carry out justice. Anything outside of that duty is moraly reprehensible.

[FreeDomSy-nkue]

I'm having a hard time trying to understand how these numbers 4:10 made it to court and actually won a case! What's the probability of that, given that the jury at least went to elementary school? Give me some Bayesian math!

[feyetho]

love that Kevin used a photo of recently deceased Betty White as the "little old lady". This video was released 5 days before her demise. Little macabre

[robertturley]

1 out of 12 million seems like plenty of room for reasonable doubt.