Smokers who are paid to quit succeed far more often than those who get no cash reward, according to a new study that provides some of the strongest evidence yet that financial incentives can help change such behavior.

The study, one of the largest of its kind, comes at a time when more employers, schools and other institutions are paying people to do everything from lose weight to improve their grades. The latest findings were published in this week's New England Journal of Medicine.

Smoking is one of the nation's biggest causes of premature death. It is believed to kill about 480,000 Americans a year. About 20% of all U.S. adults smoke, which is down from about 25% 10 years ago. Although most smokers say they want to quit, research in recent years indicates that less than 3% of those who try every year succeed in doing so permanently.

For the new study, researchers, led by a team from the University of Pennsylvania, tracked 878 General Electric Co. employees from around the country for a year and a half in 2005 and 2006. Participants, who smoked an average of one pack of cigarettes a day, were divided into two groups of roughly equal size. All received information about smoking-cessation programs.

Members of one group also got as much as $750 in cash, with the payments spread out over time to encourage longer-term abstinence. Those participants got $100 for completing a smoking-cessation program, $250 if they stopped smoking within six months after enrolling in the study, and $400 for continuing to abstain from smoking for an additional six months.

All participants were contacted three months after they enrolled in the study and periodically after that. Those who said they had stopped smoking at any point during the study were asked to submit saliva or urine samples for testing so that their claims could be verified.

About 14.7% of the group offered financial incentives said they had stopped smoking within the first year of the study, compared with 5% of the other group. At the time of their last interview for the 18-month study, 9.4% of the paid group was still abstaining compared with 3.6% of those who got no money.

Smoking experts say previous studies have found little clear evidence that such financial incentives help in getting smokers to quit, although most have involved far fewer patients and much smaller incentives.

The study 'shows that incentives work,' said Steven Schroeder, director of the Smoking Cessation Leadership Center at the University of California, San Francisco, who wasn't involved with the research. Helen Darling, president of the National Business Group on Health, a professional organization, said the findings give employers solid evidence that such incentives can help them save money on health-care costs for employees. 'You'd prefer not to pay them, but it's worth it,' she said.

一项最新研究显示，拿了钱戒烟的成功率要远远超过那些没钱拿的，这是财务激励有助于改变吸烟行为的一项最有力的证据。

在同类项目中规模最大的这项研究推出之际，正值当今越来越多的雇主、学校和其他机构花钱鼓励人们做从减肥到提高分数的各种事情。这项最新研究发表在上周的《新英格兰医学杂志》(New England Journal of Medicine)上。

吸烟是美国人最大的早逝原因之一。据称美国每年大约有48万人死于吸烟。目前美国成年人大约有五分之一吸烟，这个比例低于十年前的四分之一。尽管大多数吸烟者表示自己愿意戒烟，但近年来的研究显示，每年都尝试戒烟的人只有不到3%完全戒除了烟瘾。

从2005年到2006年的一年半时间，宾夕法尼亚州大学的一个研究小组对通用电气(General Electric Co.)分布在美国各地的878名员工进行了此项研究。这些研究对象平均每天吸一包烟，他们被分成人数相当的两个小组。所有人都被告知了这个戒烟项目的有关信息。

其中一个小组的研究对象可以拿到总计750美元的现金；这笔钱分步发放，以鼓励研究对象更长期的远离烟瘾。这些研究对象完成一个戒烟项目后就可以拿到100美元，登记参加研究之后六个月内不再复吸还可以得到250美元，再坚持六个月不 烟就能收获400美元的奖金。

在登记参加研究之后三个月，研究人员联络了所有研究对象，并在此后定期回访。那些表示研究过程中一直没吸烟的人会被要求提交唾液或尿液样本用于测试，以便验证他们自述是否属实。

提供奖金的小组中，大约有14.7%的人说他们在研究期间的头一年内没有吸烟，这个比例高于另外一组的5%。在为期18个月的此次研究最后一次回访中，付费戒烟小组有9.4%人仍然没有吸烟，而另外一个小组这个比例仅有3.6%。

戒烟问题专家表示，此前的研究没有发现明显证据表明此类财务激励有助于帮助吸烟者戒烟，不过，大多数此类研究的参加人数和奖金额都要少的多。

加州大学旧金山分校的戒烟领导中心(Smoking Cessation Leadership Center)主任施罗德(Steven Schroeder)说，这项研究显示了激励能发挥作用。他没有参与这项研究。美国企业员工健康组织(National Business Group on Health)主席达林(Helen Darling)表示，研究结果为雇主们提供了有力证据，表明此类激励能帮助它们减少对员工的医疗成本。她说，你当然更希望不付钱，但这么做值得。