Last week the Pew Center on the States produced a report highlighting the statistic that the prison and jail population has topped 1% of the total population. The press release is here and the full report is here. In reaction, Investors Business Daily had this editorial noting that prison increases coincided with a dramatic drop in crime. Paul Cassell had this post at the Volokh Conspiracy with a similar graph making largely the same point.
The graph above shows the rate of violent crime (FBI violent index crimes per 100,000 population, in red on the left scale) and the number of prisoners in each year divided by the number of violent crimes in the same year (in blue on the right scale).
Our position has always been that the prison population relative to the crime rate is a more meaningful number than the ratio to the general population. The former is the ratio that tells us how severe or how lax our sentencing policies are. The overall incarceration rate that Pew and others cite is actually the product of two factors representing two different decisions: (1) the crime rate, caused by the decisions of individuals to commit crimes, and (2) the rate at which society incarcerates criminals, which in turn is the product of its ability to apprehend and convict them and its decision on punishment of those it does convict. The factors must be separated to evaluate the effect of these different decisions by different actors.
The blue line shows that the United States did indeed go "soft" in sentencing in the 1960s and 1970s. In 1960, we had 74 people locked up for every 100 violent crimes committed in that year. By 1974, that ratio had dropped to less than a third of its previous value, only 22. In the same period, violent crime skyrocketed from 161 per 100k population to 461. Sentencing then got tougher -- gradually at first and then sharply in the 1990s. Violent crime fell, but not all the way back to its early levels.
As we have noted many times, (1) correlation does not prove causation, and (2) many factors go into determining crime rates. The extent to which soft sentencing caused the crime increase and tough sentencing caused the crime drop remains debatable. However, among serious scholars, even those opposed to tough sentencing have to grudgingly admit that sentencing is a substantial factor. A book titled The Crime Drop in America was published in 2000, edited by Alfred Blumstein and Joel Wallman. Chapter 6 is The Limited Importance of Prison Expansion, by William Spelman. Despite the dismissive title, Spelman concedes in the end, "The crime drop would have been 27 percent smaller than it actually was, had the prison buildup never taken place."
Other estimates run higher, of course. But let's take the opponents' estimate as a floor. They certainly would not have fudged it upward, so we can safely proceed on the assumption that 27% or more of the crime drop was caused by tougher sentencing. In the social sciences, a variable that explains 27% of the outcome is considered a large effect size.
More importantly, think of what this means in human terms. If violent crime rates in the years 1995-2004 were 27% lower than the average of the 1980s because we got tough, that means nearly half a million people were not robbed, almost 19,000 were not raped, and another nearly 19,000 were not murdered as a result of those policies. Remember, these stunning numbers are calculated using the other side's estimate. If more of the crime drop is attributable to tough sentencing, the real numbers are even higher.
It is indeed regrettable that the downward spiral of our culture and the decline of personal responsibility have reached a point that 1 in 100 persons have chosen to commit crimes for which they are incarcerated. We certainly can and should reexamine individual laws to see where changes should be made. For example, the law counting 5 grams of crack cocaine the same as 500 grams of powder for sentencing purposes -- proposed and supported by liberal Democrats when it was enacted -- is certainly overripe for such reexamination. But we need to be very careful.
The soft sentencing policies of the 1960s were a disaster. Many innocent people paid dearly, in many cases mortally, for the policymakers' delusion that they knew how to "fix" criminals and we didn't need "harsh" sentences any more. We must not repeat that mistake.