可容忍的通胀，不可容忍的不确定性
Tolerable Inflation, Intolerable Uncertainty
- Banque de France（法国银行）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文发现数值通胀目标虽锚定预期，但最优容忍份额不可识别，导致不确定性随超调累积；提出归一化不确定性修正，在法国贷款数据上显著改善对利率的解释力。
AI中文摘要：
数值通胀目标锚定预期。在整个欧元区和美国的专业预测、通胀互换和期权以及实际通胀中，通胀不确定性在公布的数字处被压缩，并恰好在该处出现拐点。本文识别了这种设计的一种成本，据我们所知，这种成本此前未被展示过，并且仅出现在二阶矩中。在主流新凯恩斯模型中，容忍供给冲击产生的部分通胀是最优的，但最优容忍份额无法被识别：最优的“看穿”和有效目标的不合理漂移在通胀历史上是观测等价的，因此中央银行无法证明一个合理的偏离是合理的，无论是事后还是实时。持有有限、异质性耐心的主体随后产生的预测方差在目标以下平坦，并随预期超调量线性上升——这是一笔观测等价账单，在公布的数字处为零，并随通胀在目标之上的点年数累积。该数字的一阶收益仍然成立；成本改变的是通胀不确定性必须如何衡量。与目标的距离解释了专业预测方差变异的70%，而账单位于该成分之内；归一化不确定性——据我们所知是首次此类修正——将其移除。这种清除显著改变了推断：在法国贷款层面数据上，原始离散度与企业贷款利率无关，而清除后指标的一个标准差与利率高出89个基点相关，跨国增长和时间序列结果也类似地变化。传统的通胀不确定性衡量部分记录的是通胀与其锚的距离，而非对前景的不确定性。
英文摘要：
Numerical inflation targets anchor beliefs. Across euro-area and US professional forecasts, inflation swaps and options, and realized inflation, uncertainty about inflation is compressed at the announced number and kinks exactly there. This paper identifies a cost of the same design that, to our knowledge, has not been shown before, and that appears in second moments only. Within the workhorse New Keynesian model, tolerating part of the inflation a supply shock produces is optimal, yet the optimal tolerated share is not identified: optimal look-through and an unwarranted drift of the effective target are observationally equivalent in the inflation history, so a central bank cannot demonstrate that a warranted deviation is warranted, ex post as much as in real time. Agents holding finite, heterogeneous patience then generate predictive variance that is flat below the target and rises linearly with the expected overshoot above it -- an observational-equivalence bill, zero at the announced number and accumulating with the point-years inflation spends above it. The first-order benefit of the number stands; what the cost changes is how inflation uncertainty must be measured. The distance from target explains 70% of the variation in professional forecast variance, and the bill lies within that component; Normalized Uncertainty -- to our knowledge the first such correction -- removes it. The purge changes inference substantially: on French loan-level data, raw dispersion is unrelated to corporate loan rates, while one standard deviation of the purged measure is associated with rates 89 basis points higher, and cross-country growth and time-series results shift similarly. Conventional measures of inflation uncertainty partly record inflation's distance from its anchor rather than uncertainty about the outlook.
