He was amazed at how much his daughter was learning from Minecraft; she solved problems on her own, developed a spatial understanding in the game, and accelerated her reading and writing skills because she wanted to be able to interact with other players, he said.

With more than 18 million downloads to date, Minecraft is the best-selling computer game of all time; the game’s free-form structure has made it popular with kids and adults alike. But little by little, teachers, parents, and students have discovered that the game can be used for educational purposes, too.

The most reliable measure of violent crime is the homicide rate. Americans kill one another at a much higher rate – double, quadruple, or more – than do residents of comparable western European nations. This gap persists despite a roughly 40 percent drop in our homicide rate in the last 15 years or so. Americans have been notably more violent than western Europeans since about the mid- or late 19th century.

Violent crime went down in America again last year. According to preliminary statistics from the FBI, the number of violent crimes dropped by about 5 percent from 2008 to 2009. Given population growth, that means that the rate of violent crime dropped even more. (So did property crime.)

The US homicide rate, which has declined substantially since 1992 from a rate per 100,000 persons of 9.8 to 4.5 in 2013, is still among the highest in the industrialized world. There were 13,716 homicides in the United States in 2013, including non-negligent manslaughter.[42] (666,160 murders from 1960 to 1996).[43] In 2004, there were 5.5 homicides for every 100,000 persons, roughly three times as high as Canada (1.9) and six times as high as Germany (0.9).[44][45] A closer look at The National Archive of Criminal Justice Data indicates that per-capita homicide rates over the last 30 plus years on average, of major cities, New Orleans' average annual per capita homicide rate of 52 murders per 100,000 people overall (1980–2012) is the highest of U.S. cities with average annual homicide totals that were among the top 10 highest during the same period.

The United States has the highest incarceration rate in the world (which includes pre-trial detainees and sentenced prisoners).[39] As of 2009, 2.3 million people were incarcerated in the United States, including federal and state prisons and local jails, creating an incarceration rate of 793 persons per 100,000 of national population.[39] During 2011, 1.6 million people were incarcerated under the jurisdiction of federal and state authorities.[40] At the end of 2011, 492 persons per 100,000 U.S. residents were incarcerated in federal and state prisons.[40] Of the 1.6 million state and federal prisoners, nearly 1.4 million people were under state jurisdiction, while 215,000 were under federal jurisdiction.[40] Demographically, nearly 1.5 million prisoners were male, and 115,000 were female, while 581,000 prisoners were black, 516,000 were white, and 350,000 were Hispanic.[40]

: The number of police officers increased considerably in the 1990s.[8] On September 16, 1994, President Bill Clinton signed the Violent Crime Control and Law Enforcement Act into law. Under the act, over $30 billion in federal aid was spent over a six-year period to improve state and local law enforcement, prisons and crime prevention programs.[9] Proponents of the law, including the President, touted it as a lead contributor to the sharp drop in crime which occurred throughout the 1990s,[9] while critics have dismissed it as an unprecedented federal boondoggle.[9]

After World War II, crime rates increased in the United States, peaking from the 1970s to the early 1990s. Violent crime nearly quadrupled between 1960 and its peak in 1991. Property crime more than doubled over the same period. Since the 1990s, however, crime in the United States has declined steeply. Several theories have been proposed to explain this decline:

In the long term, violent crime in the United States has been in decline since colonial times.[6] However, during the early 20th century, crime rates in the United States were higher compared to parts of Western Europe. For example, 198 homicides were recorded in the American city of Chicago in 1916, a city of slightly over 2 million at the time. This level of crime was not exceptional when compared to other American cities such as New York, but was much higher relative to European cities, such as London, which then had three times the population but recorded only 45 homicides in the same year.[7]

According to the FBI, index crime in the United States includes violent crime and property crime.[5] Violent crime consists of four criminal offenses: murder and non-negligent manslaughter, forcible rape, robbery, and aggravated assault; property crime consists of burglary, larceny, motor vehicle theft, and arson.[5]

Crime in the United States has been recorded since colonization. Crime rates have varied over time, with a sharp rise after 1963, reaching a broad peak between the 1970s and early 1990s. Since then, crime has declined significantly in the United States,[1] and current crime rates are approximately the same as those of the 1960s.[2]

For a list of criminal organizations in the United States, see List of criminal enterprises, gangs and syndicates § United States.