“We found that in a majority of the categories we examined, contract prisons incurred more safety and security incidents per capita than comparable BOP institutions,” the report concluded, based on its analysis of 14 private prisons and 14 public prisons from fiscal years 2011 to 2014.
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The OIG report isn’t the first to indicate private prisons are worse off, although it is the most recent one. A 2001 report from the Department of Justice found the rate of inmate-on-inmate violence at private prisons was 38 percent higher than the rate at public prisons. And in a four-month undercover investigation, reporter Shane Bauer witnessed high levels of violence — particularly stabbings, which seemingly went underreported in official numbers — and lockdowns at a private prison in Louisiana.

The problem in private facilities generally follows the same theme: They seem to have big problems staffing up, because the for-profit motive for private prisons incentivizes them to keep salaries and staff numbers low. As a result, the limited number of guards can’t handle, deter, or stop outbreaks of violence as effectively as a bigger staff in, say, a public prison can.

Wikipedia wrote:
In 2012, CCA spent $1,790,000 lobbying Congress and federal bureaucracies on issues relating to homeland security, law enforcement, immigrant detention, and information disclosure legislation