If you instituted a policy to require less evidence to convict black defendants, you would convict more black defendants, which would make the measured “base rates for violence among blacks” go up, which would mean that you could need even less evidence to convict, which...
No, you’d just need to keep track of how often demographic considerations influenced the outcome, so that any measure of “base rates for violence among blacks” you use for such decisions is independent of the policy.
(That’s not to say that such a policy would be a good idea of course)
It’s not clear that “the base rates for violence among blacks is higher” is meant to be measured by convictions. I interpreted it to be based on sociological data, for example, and in that case there would be no feedback loop. Pinker didn’t cite a source, unfortunately. A very quick stroll past Google Scholar 12 shows that a common source used is arrest data in the FBI’s Uniform Crime Report. Plainly there are also important ways in which arrest data may be biased against blacks, but I’m hesitant to simply dismiss a finding based on that difficulty as I’m willing to bet that researchers in the field would have attempted to account for the difficulty.
The right kind of data would come from things like the National Crime Victimization Survey which collects data outside the criminal justice system. The base rate for the offender in a violent crime being black, is, according to that survey, lower than the probability that a given person arrested for a violent crime is black. So it looks to me that the evidence is long screened out by the time the case gets to the court room.
Right. I’m comparing particular categories of crime—reports from robbery victims to arrests for robbery, reports of rape to arrests for rape etc. I’m definitely not comparing total arrests for violent crimes to reports of violent crimes minus homicide.
I presumed as much, but that problem may still be noticeable: every rape that’s also a murder won’t get counted. I don’t know how frequently the various violent crimes are paired with murder, though, or how large the difference between reported victimization and arrests are.
If you instituted a policy to require less evidence to convict black defendants, you would convict more black defendants, which would make the measured “base rates for violence among blacks” go up, which would mean that you could need even less evidence to convict, which...
No, you’d just need to keep track of how often demographic considerations influenced the outcome, so that any measure of “base rates for violence among blacks” you use for such decisions is independent of the policy.
(That’s not to say that such a policy would be a good idea of course)
It’s not clear that “the base rates for violence among blacks is higher” is meant to be measured by convictions. I interpreted it to be based on sociological data, for example, and in that case there would be no feedback loop. Pinker didn’t cite a source, unfortunately. A very quick stroll past Google Scholar 1 2 shows that a common source used is arrest data in the FBI’s Uniform Crime Report. Plainly there are also important ways in which arrest data may be biased against blacks, but I’m hesitant to simply dismiss a finding based on that difficulty as I’m willing to bet that researchers in the field would have attempted to account for the difficulty.
The right kind of data would come from things like the National Crime Victimization Survey which collects data outside the criminal justice system. The base rate for the offender in a violent crime being black, is, according to that survey, lower than the probability that a given person arrested for a violent crime is black. So it looks to me that the evidence is long screened out by the time the case gets to the court room.
Note that the NCVS requires that the victims survive, and does not collect data on crimes like murder, which may cause systematic differences.
Right. I’m comparing particular categories of crime—reports from robbery victims to arrests for robbery, reports of rape to arrests for rape etc. I’m definitely not comparing total arrests for violent crimes to reports of violent crimes minus homicide.
I presumed as much, but that problem may still be noticeable: every rape that’s also a murder won’t get counted. I don’t know how frequently the various violent crimes are paired with murder, though, or how large the difference between reported victimization and arrests are.
Good point.