I agree that the Supreme Court cases are not on point, but the discussion of chains of evidence is worth thinking about. If we accept hearsay exceptions based on reliability (and I think exceptions for things like business records have little other justification), then hearsay within hearsay is perhaps not treated correctly. Once evidence is admitted, it is admitted—the judge doesn’t instruct the jury to give less weight to hearsay within hearsay.
But probability says that if business records are 80% reliable, and present sense impressions are 70% reliable, a business record that is based on a present sense impression is 56% reliable (if I did the math right). That’s unintuitive to the jury, and the legal system makes no effort to correct for this misunderstanding of statistics.
Edit:
And the description of the judge sifting out evidence is a good explanation for non-lawyers.
But probability says that if business records are 80% reliable, and present sense impressions are 70% reliable, a business record that is based on a present sense impression is 56% reliable (if I did the math right).
Well, .7*.8=.56, certainly, but personally I would not be so casual about assuming that the two failure rates are independent.
I agree that the Supreme Court cases are not on point, but the discussion of chains of evidence is worth thinking about. If we accept hearsay exceptions based on reliability (and I think exceptions for things like business records have little other justification), then hearsay within hearsay is perhaps not treated correctly. Once evidence is admitted, it is admitted—the judge doesn’t instruct the jury to give less weight to hearsay within hearsay.
But probability says that if business records are 80% reliable, and present sense impressions are 70% reliable, a business record that is based on a present sense impression is 56% reliable (if I did the math right). That’s unintuitive to the jury, and the legal system makes no effort to correct for this misunderstanding of statistics.
Edit: And the description of the judge sifting out evidence is a good explanation for non-lawyers.
Well, .7*.8=.56, certainly, but personally I would not be so casual about assuming that the two failure rates are independent.