主要内容出自Gregor Boehl的博客，其中更多间接的引用不再赘述，选取部分感兴趣的主题。

Monetary Economics

• The Paradox of Flexibility: Greater price flexibility worsens the recession in a liquidity trap. (Diba and Loisel, 2021, JME)

灵活性悖论：更大的价格灵活性加剧了流动性陷阱中的衰退

• The Neo-Fisherian Puzzle: With simple model tweaks, low interest rates are disinflationary. (Schmitt-Grohé and Uribe, 2017, AER)

Neo-Fisherian之谜：通过简单的模型调整，低利率是通货紧缩的。长期来看，持续保持低利率可能不会引发通胀上升，反而可能导致通胀率下降；同样地，持续维持高利率可能不会遏制通胀，反而可能导致通胀率上升。可能与理性预期、货币规则稳定性、菲利普斯曲线平坦化、货币价值与利率的关系等有关。

• The Natural Rate Puzzle: The natural rate of interest seems to be steadily declining for at least the last two decades. (Laubach and Williams, 2016, Business Economics)

自然利率之谜：至少在过去二十年中，自然利率似乎一直在稳步下降。可能的解释包括人口老龄化导致的储蓄过剩、投资需求疲软、技术进步与全球化带来的生产率增长放缓、风险厌恶情绪上升导致的安全资产需求增加、以及结构性因素（如债务积压、金融监管强化等）导致的信贷供给受限等。

• The Forward Guidance Puzzle: An expected monetary policy shock in the far future has the same impact as the same shock in the current period. (Del Negro, Giannoni and Patterson, 2015, FED NY Working Paper)

前瞻指引之谜：遥远未来的预期货币政策冲击与当前时期的相同冲击具有相同的影响

• The Flat Phillips Curve Puzzle: Estimates of the coefficient of the NK-PC and regression coefficients of inflation on unemployment are very close to zero (equivalent to the missing deflation/inflation puzzle). (e.g. Ball and Mazumder, 2011, NBER Working Paper)

平坦菲利普斯曲线之谜：NK-PC系数和通货膨胀对失业率的回归系数的估计非常接近于零 （相当于缺失的通货紧缩/通货膨胀之谜）。

• The Monetary Transmission Puzzle: Intertemporal substitution is a too simplistic view on the monetary transmission mechanism. (e.g. Jappelli and Pistaferri, 2010, Annual Review of Economics)

货币传导之谜：跨期替代是对货币传导机制过于简单化的观点。

• The Inflation Persistence Puzzle: Staggered nominal contracts generate price persistence, but fail to account for inflation persistence. (Fuhrer and Moore, QJE, 1995)

通胀持续之谜：交错的名义合约产生价格持久性，但未能解释通胀持久性。

• The Liquidity Puzzle: The failure of identified monetary policy disturbances to create negative short-run correlations between nominal interest rates and the money stock. (Mishkin, JoF, 1981)

流动性之谜：已确定的货币政策干预未能在名义利率和货币存量之间产生短期负相关性。

Economics of Inequality

• The Rising Markup Puzzle: Markups on marginal costs and hence the profit share is increasing. (e.g. Hall, 2018 NBER Working Paper)

加价之谜：边际成本加价，因此利润份额正在增加。

• The Fast-Transition Puzzle: Current models do not do well in explaining the rapid rise in wealth concentration since the 1980s. (Gabaix, Lions and Moll, 2016, Econometrica)

快速转型之谜：目前的模型不能很好地解释自1980年代以来财富集中度的迅速上升。

Macrofinance

• The Credit Spread Puzzle: Structural models of default calibrated to historical default rates, recovery rates, and Sharpe ratios typically generate Baa–Aaa credit spreads that are significantly below historical values. (Chen, Collin-Dufresne, and Goldstein, 2009, RFS)

信用利差之谜：根据历史违约率、回收率和夏普比率校准的违约结构模型通常产生的 Baa-Aaa 信用利差明显低于历史值。

• The Bond Premium Puzzle: Macro models cannot explain the large and variable premium on long-term vs short-term bonds. (Rudebush and Swanson, 2008, JME)

债券溢价之谜：宏观模型无法解释长期债券与短期债券的巨大可变溢价。

• The Declining Savings Puzzle: The U.S. personal saving rate declined from 11 percent to 3 percent between 1980 and 2007. (Guidolin and Jeunesse, 2007 St. Louis Fed Review)

储蓄下降之谜：1980年至2007年间，美国个人储蓄率从11%下降到3%

• The Price Puzzle: In many studies, the Fed Fund rate is positively correlated with inflation. (Bernanke and Blinder, 1992, AER)

价格之谜：在许多研究中，联邦基金利率与通货膨胀呈正相关。

• The Risk-Free Rate Puzzle: Why is the risk-free rate so low if agents are so averse to intertemporal substitution? – Related to the Equity Premium Puzzle. (Weil, 1989, JME)

无风险利率之谜：如果代理人如此反对跨期替代，为什么无风险利率如此之低？——与股权溢价之谜有关。

• The Equity Premium Puzzle: Macro models require an implausibly high degree of risk aversion to explain the premium of stocks over “safe” bonds. (Mehra and Prescott, 1985, JME)

股票溢价之谜：宏观模型需要难以置信的高度风险厌恶来解释股票相对于“安全”债券的溢价。

• The Equity Volatility Puzzle: Why is the volatility of stock returns so high (in relation to the short-term real interest rate)? (Campbell, 2003, The American Economist; Shiller, 1981, AER)

股票波动性之谜：为什么股票回报的波动性如此之高（相对于短期实际利率）？

International Macro

• The International Elasticity Puzzle: The elasticity between foreign and domestic goods necessary to match fluctuations in trade balances, and the elasticity needed to account for trade growth patterns are hard to reconcile. (Ruhl, 2008, unpublished manuscript)

国际弹性之谜：匹配贸易差额波动所需的外国和国内商品之间的弹性与考虑贸易增长模式所需的弹性难以调和。

• The International Diversification Puzzle: Although international financial markets are highly integrated across the more well-developed countries, investors nevertheless hold portfolios that consist nearly exclusively of domestic assets. (Baxter and Jermann, 1997, AER)

国际多元化之谜：尽管国际金融市场在较发达的国家高度一体化，但投资者持有的投资组合几乎完全由国内资产组成。

Labor & Wages

• Productivity Puzzle: Labor productivity growth in major advanced economies has markedly slowed since the Great Recession, particularly in the UK. (Tenreyro, 2018, BoE spreech)

生产率之谜：自大衰退以来，主要发达经济体的劳动生产率增长明显放缓，尤其是在英国。

• The Falling Labor Share Puzzle: While classically assumed to be constant, the labor share is falling since the 1980s. (Karabarbounis and Neiman, 2014, QJE)

下降的劳工份额之谜：虽然传统上被认为是恒定的，但自1980年代以来，劳动份额一直在下降。

• The Paradox of Toil: (Anticipated) positive supply shocks are contractionary in a liquidity trap. (Eggertson, 2010, NY-FED Staff Reports)

辛勤劳作悖论：（预期的）积极的供应冲击在流动性陷阱中是收缩的。 在经济衰退期间，失业率上升，收入下降，人们对未来经济前景感到担忧。为了应对这些不利条件，许多劳动者会选择增加工时，接受更低薪资，提高工作效率。但从宏观经济角度看，这些个体层面的努力和应对措施可能导致意想不到的负面后果。悖论成因可能包括，总需求不足：消费者信心下降，支出减少，企业投资意愿低迷。个体劳动者增加供给（通过增加工时、降低薪资要求或提高生产效率），反而可能因为收入减少或分配不均而进一步抑制消费需求。乘数效应减弱：劳动者增加工作努力减少了的闲暇时间，降低了消费支出，消费减少会导致乘数效应减弱，即每单位新增产出对总需求的拉动作用下降。这使得原本就疲软的经济更加难以恢复增长动力。通缩压力：劳动者愿意接受更低薪资，导致整体工资水平下降，引发或加剧通缩压力。通缩会增加实际债务负担，抑制投资和消费，进一步拖累经济增长。失业加剧：尽管个体劳动者通过增加工作努力提高了劳动供给，但如果总需求没有相应增长，企业可能并不需要额外的劳动力。在这种情况下，过度的劳动供给可能导致更多人失业，因为企业在降低成本的压力下会选择精简人员，而不是增加雇员。

• The Shimer Puzzle: Basic search-and-matching models cannot explain the volatility in unemployment given the observed volatility in labor productivity. (Shimer, 2005, AER)

夏默之谜：鉴于观察到的劳动生产率波动，基本的搜索和匹配模型无法解释失业的波动性。

• The Minimum Wage Puzzle: Portuguese data suggests that increasing minimum wages can lead to a decline of the worker-firms separation rate. (Portugal and Cardoso, 2006, JEEA)

最低工资之谜：葡萄牙的数据表明，提高最低工资会导致工人与企业的离职率下降。

Public Finance

• The U.S. Pulic Debt Valuation Puzzle: The market value of outstanding U.S. government debt in the exceeds the expected present discounted value of current and future primary surpluses by a multiple of U.S. GDP. (Jiang et al, 2019, NBER WP 26583)

美国公共债务估值之谜：未偿还美国政府债务的市场价值超过当前和未来基本盈余的预期现值折现值，是美国GDP的倍数。传统经济学认为债务的市场价值应等于当前和未来基本盈余的预期现值折现值，但是在低利率环境下可能不成立。传统经济学中债务负担增加应导致利率上升，现实中全球许多国家，尤其是发达国家，公共债务水平持续攀升，但市场利率（尤其是长期国债收益率）却长期处于历史低位，甚至在某些时期出现负利率。可能的原因包括但不限于债务可持续性担忧与安全资产缺乏的矛盾，非传统货币政策压低国债收益率，改变市场对债务可持续性、风险溢价以及未来利率路径的预期，全球资本流动与债务估值的关联。

• The Fiscal Price Puzzle: VAR evidence suggests that inflation tends to decline when government spending increases. (Jørgensen and Ravn, 2019, unpublished manuscript)

财政价格之谜：VAR证据表明，当政府支出增加时，通货膨胀往往会下降。传统理论通常认为政府支出增加会通过以下途径推高通货膨胀。

• The Fiscal Multiplier Puzzle: Asymptotically, the power of a fiscal expansion grows exponentially with the expected duration of a liquidity trap. (Farhi and Werning, 2016, Handbook of Macroeconomics)

财政乘数之谜：渐近地，财政扩张的力量随着流动性陷阱的预期持续时间呈指数级增长。 财政乘数的具体大小取决于多个因素，如边际消费倾向、货币流通速度、是否存在挤出效应（即财政扩张是否导致私人投资减少）以及货币政策的配合情况等

Behavioral Macro

• The Rational Expectations Puzzle: Survey evidence contradicts the rational expectations hypothesis. (Greenwood and Shleifer, 2014, ReStud)

理性预期之谜：调查证据与理性预期假说相矛盾。