The next iPhone, which Apple Inc. plans to unveil this week, could do something the White House, Congress and Federal Reserve have struggled to do: boost the U.S. economy.苹果公司计划这周发布的新一代iPhone，可以做一件白宫、美国国会和美联储都一直很难做到的事情：提振美国经济。Sales of the new iPhone could add between a quarter and a half of a percentage point to the annualized rate of economic growth in the fourth quarter, J.P. Morgan Chase Co.s chief U.S. economist Michael Feroli estimates. That could help cushion the sluggish U.S. economy from other risks in the final months of the year.摩根大通首席美国经济学家费洛里说，新iPhone的销售有望使第四季度年化经济增长率提升0.25至0.5个百分点。这可能能够帮助疲弱的美国经济在年内最后几个月应付来自其他风险的冲击。In a note to clients Monday, titled Can one little phone impact GDP?, Mr. Feroli walks through the math: J.P. Morgans equity analysts expect Apple to sell about eight million new iPhone units in the final three months of 2012.弗洛里周一向顾客发送了一份题为《小小手机能否影响GDP？》的报告，讲解了上述结论的计算过程：摩根大通股权剖析师预计苹果将在2012年最后三个月卖出约800万部新iPhone。If the phone sells for around $600, with about $200 of it counted as imported components, then $400 per phone would add to the governments measure of gross domestic product, the total value of the economys output.假如价格约为600USD，其中摩根大通算为进口零部件的部分在200USD左右，那样每部手机就会使政府统计的国内生产总值增加400USD。Even though consumers may not pay that much for the phone, because of subsidies from wireless carriers, Mr. Feroli explains that companies often report phone sales based on the price of the stand-alone product.虽然电信运营商的补贴或许会让买家不需要支付那样多钱，但费洛里讲解，企业在报告手机销售额的时候，常常是基于单个商品的价格。The bottom line: The new iPhone sales could boost GDP by $3.2 billion in the fourth quarter, or $12.8 billion at an annual rate. That is an increase of 0.33 percentage point in the annualized rate of GDP growth. It could be even higher, he says. Even a third of a percentage point would limit the risk the economy would grow more slowly than J.P. Morgans fourth-quarter growth projection of 2%.总之，新iPhone的销售额有望将第四季度的GDP提升32亿USD，折合成年率为128亿USD，等于年化GDP增长率提升0.33个百分点。弗洛里说，实质可能还会更高。就算只有三分之一个百分点，也会减少第四季度实质经济增长速度低于摩根大通预测速度2%的风险。Mr. Feroli warns that the estimate seems fairly large, and for that reason should be treated skeptically but adds: We think the recent evidence is consistent with this projection.弗洛里警告说，这个估计数字看着好像相当大，所以应当抱怀疑态度。但他也说：大家觉得最近出现的证据与这一预测相符。One clue: When the iPhone 4S became widely available last October, he writes, over half of the 0.8% increase in the nations so-called core retail sales─which exclude autos, gasoline and building materials─came in the categories of online sales and computer and software sales. The two categories together had their largest monthly increase on record.他写道，另一条线索是，当去年十月份iPhone 4S广泛上市销售时，核心零售额（排除汽车、汽油和建材）0.8%的增幅中，超越一半的增幅来自网上销售和电脑及软件销售。这两个项目加起来的月增长幅度达到有记录以来最高水平。He estimates the sales growth was due to the iPhone, which boosted overall GDP growth by a fifth to a 10th of a percentage point. The new iPhone launch will be even bigger than that, he says, making the latest estimate reasonable.费洛里估计这种增长得益于iPhone，它使整个GDP增速提升了0.1至0.2个百分点。他说，新一代iPhone是分量更大的商品，所以最新的估计是“合理”的。In the final three months of last year, the U.S. economy expanded rapidly at a 4.1% annual rate, and then slowed sharply to a 2% pace in the first quarter of this year, and 1.7% in the second quarter.去年最后三个月，美国经济年化增长率达4.1%，今年一季度大幅减速至2%，二季度又降至1.7%。Many analysts have recently lowered their forecasts for economic growth in the second half of the year for reasons including the drought, higher oil prices and uncertainty about U.S. budget policies. Last week, the forecasting firm Macroeconomic Advisers shaved its forecasts for economic growth to a 1.5% annual rate in the third-quarter and 1.4% in the fourth quarter, both down seven-tenths of a percentage point, largely due to the effect of the drought on farm output.不少剖析师近期下调了美国下半年经济增长预期，缘由包含旱灾、油价上涨及美国预算政策的不确定性。预测公司Macroeconomic Advisers上周将第三季度年化经济增长率预期下调至1.5%，将第四季度预期下调至1.4%，分别都降了0.7个百分点，理由主如果旱灾对农业产量的影响。
