> It's an old study, but Martell in Base-rate estimates of criminal behavior by homeless mentally ill persons in New York City found that "The rate of violent crimes was 40 times higher and the rate of nonviolent crimes 27 times higher in the homeless population".
It is indeed old (1995 [0]) and that's not what the paper studied or concluded. First, the study did not gather data on the homeless population, but on mentally ill people already in the criminal justice system:
* "The authors analyzed data from ... records of 77 homeless defendants and 107 domiciled defendants referred for psychiatric examination by the criminal and supreme courts ..."
Second, the paper's goals were to gather needed data on homelessness among mentally ill people in the criminal justice system, and to examine the interactions between homelessness and crime among mentally ill people:
* "The study aimed to estimate the prevalence of homelessness among mentally disordered offenders entering the criminal justice andforensic mentalhealth systems, to compare base rates of arrest for violent and nonviolent criminal charges among homeless and domiciled persons with mental illness, and to examine patterns in the categories of victims chosen ..."
Third, the conclusion was that, among mentally ill people generally (not only those charged [1]) those homeless were ~35x more likely to be charged with crimes than those domiciled, and it was somwhat even more likely that those crimes would be violent or against strangers (there's more detail in the paper). The paper says nothing about crime among the homeless population generally.
> absurd
> crack the skull of a 70 year old nurse
Do pejoratives and outrage make it more persuasive or less? More importantly, do they make it more likely or less likely that you find and express truth?
I think much less likely, because it means 1) You are dismissing a lot of information, 2) You are not examining the matter thoughtfully (being outraged), and 3) You likely have little better argument.
That also makes it less persuasive to people who are thinking critically.
[0] When crime rates were much higher. The paper: Martell, D. A., Rosner, R., & Harmon, R. B. (1995). Base-rate estimates of criminal behavior by homeless mentally ill persons in New York City. Psychiatric Services, 46(6), 596–601. https://doi.org/10.1176/ps.46.6.596
[1] Note that they gathered data only on mentally ill people charged with crimes and not on the general population of mentally ill people. The latter group's data they took from the same author's prior research.