English newspaper Guardian printed an article by Chris McGreal Sunday August 21, 2011 titled "America's serious crime rate is plunging, but why?" Washington D.C. had 482 homicides in 1991. Last year there were 131 murders in the city. New York City had the lowest number of murders in 2009 than at any time since 1963. FBI crime statistics show that serious crime - including murder, rape and robbery are at the lowest level in 48 years.
This topic has been covered in depth by many commentators, but the Guardian article looks at several competing theories to explain the reasons for the decrease in U.S. crime rates over the past 20 years. Unfortunately, there is no definitive answer at this point.
Some of the factors that contribute to the crime rate reduction are: increases in medical technology that have saved more lives of victims of violent assault; increased police intelligence and communication between agencies; cars that are more difficult to steal; the fact that people use bank and credit cards and do not carry cash as often, making robberies unproductive; homes and businesses are more likely to have alarm systems; and the popularity of crack cocaine, and the gang violence that came with it, has hugely decreased in the last two decades.
Other popular, or politically convenient theories have been disproved or seriously questioned. One sacrosanct theory was that crime rates rise increase as economic conditions worsen, however that has not been the case in the time since the Great Recession of 2008, as crime rates continue to fall. Another is that the cities of Washington and New York have strict gun ownership laws, yet cities with relaxed gun laws have seen the same decrease in crime. Likewise the increase in prison population, where the U.S. imprisons about twice the people per capita as it did in the 1980's is given credit in many quarters, but countries like Canada who have not embarked on the increased prion terms, mandatory sentenced and prison building boondoggle seen the U.S. has seen the same reductions in crime.
One interesting theory is that the removal of lead from gasoline and from paint has played a contributing factor, as lead ingestion is linked to violent behavior as children exposed to lead become teenagers and adults. Lead in the drinking water surely contributed to the fall of Rome, maybe the same factors were beginning to play out in the U.S., but have now been reversed due to the regulation of lead in paint and gasoline.
Perhaps only time will answer the important question of why the crime rates have fallen over the past 20 years. The why of it will tell us how crime can be lowered farther, and prevented more effectively in the future.