of businesses unsure of the outlook for demand and their profits. another factor holding back u. s. growth has been repeated shocks to the global economy, sometimes amplified by vulnerabilities growing out of the crisis. the effects of a number of these shocks have spilled over to the united states, including those stemming from the euro - area debt crisis as well as occasional concerns about the strength and durability of emerging market growth, especially in china. these foreign developments contributed to a 15 percent appreciation of the broad dollar since mid - 2014, which, along with weak foreign economic activity, weighed on 2 / 7 bis central bankers'speeches u. s. export growth. concern over the strength of foreign demand also contributed to a steep decline in the price of oil at around the same time. historically, lower oil prices have been a positive for u. s. growth, but the tremendous rise in domestic shale oil production over the past decade has created a powerful counterweight that has offset some of the benefit of lower prices. in the immediate aftermath of the decline in oil prices, investment in the energy sector fell off precipitously, pushing down aggregate investment as well. regarding structural explanations for slow growth, demographics are likely playing a role. in a development that predates the crisis, relatively flat labor input, as measured by hours worked, has weighed on growth. in part, the sluggishness of labor input just reflects long - term demographic trends as baby boomers age and retire. 5 perhaps most important in explaining the growth slowdown has been the lackluster increase of productivity in recent years. labor productivity has averaged an annual growth rate of only 3 / 4 percent since 2011, far below the 2 - 1 / 4 percent pace prevalent over the two decades leading into the financial crisis. why has productivity growth been so anemic? a number of theories have been raised, but there does not appear to be a clear answer — and certainly not a consensus answer. one school of thought is that productivity growth has not slowed down much at all ; rather, new technologies and products have made economic output harder to measure. 6 it is not difficult to think of technological developments that have had a deep and pervasive effect on our daily lives ( smartphone apps, for example ) but perhaps in a manner that is difficult to describe in the existing vocabulary of economic statistics. however, the counter to this argument is that troubles in measuring “ newness ” are not especially new. measuring the effect of

spring ), pp. 165 – 86. 1 the views i express here are my own and not necessarily those of the federal reserve board or the federal open market committee. 2 2. the imf ’ s most recent forecast was released in january and is available on its website at www. imf. org / en / publications / weo / issues / 2018 / 01 / 11 / world - economic - outlook - update - january - 2018. 3 3. the most recent summary of economic projections, an addendum to the minutes of the december 2017 fomc meeting, is available on the www. federalreserve. gov / monetarypolicy / fomcminutes20171213ep. htm. board ’ s website at 4 4. reinhart and rogoff ( 2009 ) document the lasting effect that downturns related to a financial crisis can have on economic growth. 5 5. see aaronson and others ( 2014 ). 6 / 7 bis central bankers'speeches 6 6. see hatzius and others ( 2016 ) for an overview of some issues that new technologies and products may be introducing into the measurement of gdp and productivity. 7 7. see syverson ( 2017 ) and byrne, fernald, and reinsdorf ( 2016 ). 8 8. gordon ( 2016 ) argues that recent technological advances have been relatively minor compared with the large advances that drove rapid increases in productivity in the past. 9 9. see decker and others ( 2016 ). 10 10. for a historical measure of the fiscal policy ’ s contribution to gdp growth, see the hutchins center fiscal impact measure, available on the brookings institution website at www. brookings. edu / interactives / hutchinscenter - fiscal - impact - measure. 11 11. see brynjolfsson and mcafee ( 2014 ) and baily, manyika, and gupta ( 2013 ). 12 12. brynjolfsson, rock, and syverson ( 2017 ) argue that lags in the adoption of new technology could explain the paradox between apparent advances in technology and continued weak productivity growth. they are referring specifically to artificial intelligence, but the argument could also hold for other fields. 13 13. see board of governors ( 2018 ). 7 / 7 bis central bankers'speeches