【正文】 otential victims are more likely to possess a firearm, then more gun ownership may lead to a reduction in criminal activity. If instead guns increase the payoff to criminal activity, or simply increase the likelihood thatany particular confrontation will result in a victim39。s change they were still locked up, rather than out on the streets mitting crime. On the other hand, if incapacitation is the only effect, then such laws can lead to the imprisonment of individuals long after their active criminal years are over. Such a geriatric prison population is an extremely inefficient use of resources, since criminal activity declines rapidly as individuals age. The fact that both deterrence and incapacitation play an important role in reducing crime． The authors conclude that sentence enhancements that are broader in scope and less punitive, may ultimately prove more effective in fighting crime than the threestrikes laws since the former are more likely to actually be enforced. 。ll be victimised. Specifically, the immediate decreases in crime roughly half of the overall decline therefore must be attributable to deterrence. Criminals, fearing the harsher sentences that awaited them, reduced their illegal activity. Sentence Enhancements Reduce Crime. The law requiring longer sentences has been effective in lowering crime. Within three years, crimes covered by the law fell an estimated 8 percent. Seven years after the law changed, these crimes were down 20 percent. In recent years, almost every state has adopted some form of sentence enhancements as a way to fight crime. These laws e under a variety of names including determinate sentencing laws, and repeatoffender enhancements. Regardless of the name, they all share one mon feature: stiffer punishments for offenders mitting the most serious crimes. Daniel Kessler and Steven Levitt analyze the oute of one such law, they find that the law requiring longer sentences has been effective in lowering crime.(NBER Working Paper No. 6484) The fact that the impact of the law39。s paper that stiff sanctions will do the job when it es to bating youth crime. But Levitt is careful to emphasize that his analysis does not suggest a clear public policy responsemore needs to be known about what works and what doesn39。 What Reduced Crime in New York City During the 1990s, crime rates in New York City dropped dramatically, even more than in the United States as a whole. Violent crime declined by more than 56 percent in the City, pared to about 28 percent in the nation as whole. Property crimes tumbled by about 65 percent, but fell only 26 percent nationally. Many attribute New York39。 事實上，近幾年來法律的改良持續(xù)穩(wěn)步的增長對于這段時間減少犯罪也是很有幫助的。不管它們涉及的領域如何，它們都有一個共同的特點：嚴厲懲罰罪犯犯下的嚴重罪行。短短的 三年間，由于法律涵蓋的深度廣度的加強和擴大，犯罪率明顯下跌 8%左右。應討論