S5 Ep49: How did inflation get so high?

Episode Summary

Executive Summary: Ricardo Reis argues the 2021-22 inflation surge was not a single-shock story but a policy failure shaped by four interacting forces: rapid post-COVID demand recovery, rising inflation expectations, weakening central-bank credibility, and overreliance on a low neutral-rate (R-star) worldview. He says central banks should have tightened in late 2021 and are now regaining credibility.

Main Topics: Why inflation surged after years of stability (Priority: 5/5): Reis frames the inflation episode as a break from two decades of very low, stable inflation in advanced economies, and argues that this history makes policy choices central to explaining the reversal. COVID recovery and delayed policy tightening (Priority: 5/5): He says stimulus was appropriate in 2020 but should have been withdrawn as the economy rebounded in 2021; central banks stayed too accommodative for too long despite falling unemployment and rising inflation. Inflation expectations and persistence (Priority: 4/5): Temporary shocks became persistent because households and markets began to expect higher inflation, making the initial supply shocks harder to contain. Credibility and the Phillips curve (Priority: 4/5): Reis argues central banks lost some credibility by reacting late, which steepened the Phillips curve and reduced the effectiveness of policy on inflation while leaving real activity less affected. R-star and the low-rate worldview (Priority: 4/5): He cautions that central banks overlearned from a falling neutral rate and deflation fears, making them too dovish even as the inflation environment changed. Interconnected causes, not a single culprit (Priority: 3/5): The paper’s conclusion is that shocks, expectations, credibility, and R-star interacted; no single factor explains the inflation burst on its own.

Key Arguments: Two decades of low inflation were not just luck; they were strongly associated with independent central banks using inflation targets and interest-rate setting. The 2020 stimulus response was initially correct, but by late 2021 it should have been reversed as economies recovered faster than expected. Supply shocks from transport disruptions, labor shortages, migration effects, and energy prices raised inflation, but central-bank persistence with ultra-loose policy amplified them. Inflation expectations were already showing signs of de-anchoring in 2021, especially in household surveys at short horizons. Credibility matters at longer horizons: once markets doubt the central bank’s commitment, inflation becomes harder to bring back to target. Late tightening worsened credibility; earlier action would likely have prevented some of the inflation persistence. The special role of government bonds and the decline in measured R-star may have led policymakers to overemphasize deflation risk and fiscal/monetary stimulus. The four explanations are complementary: shocks triggered expectations, expectations weakened credibility, and low-R-star beliefs delayed tightening. He believes current policy is moving back toward optimal and that inflation could return to 2% by 2024-25 if credibility is maintained.

Data Points: Period of stable inflation: 20–30 years - Advanced economies experienced very stable inflation before 2021. Inflation target: 2% - Used as the benchmark around which inflation variance was historically low. Potential timing for rate hikes: Fall or winter 2021 - Reis says central banks should have begun hiking by then. Very low unemployment: Historically minimum levels - By late 2021 unemployment in the US, Euro area, and UK was falling to very low levels. Confidence in inflation risk options: ~10% implied probability - Inflation insurance prices in January 2022 implied roughly a 10% chance of inflation getting out of hand. Time horizon for inflation insurance: 5 years - Example used to illustrate market credibility and tail-risk pricing. Short-horizon expectation deterioration: 1–2 years - Household surveys showed early signs of de-anchoring at short horizons last summer. Recovery outlook: 2024–25 - Reis’s optimistic estimate for returning to 2% inflation if policy remains strong.

Pivotal Quotes: "it is because central banks deserve so much credit for 25 years of low inflation that I think it is fair to point to the mistakes done in the last year" — Ricardo Reis: Explaining why current inflation should be analyzed as a policy problem, not just a set of external shocks. "if you had started earlier, that credibility I think would not have been lost" — Ricardo Reis: Arguing that earlier tightening in 2021 would have reduced the loss of central-bank credibility. "we have already been back to optimal" — Ricardo Reis: His assessment that recent central-bank actions have improved and are restoring credibility.

Implications: The episode argues that inflation control still works, but only if central banks react faster to recovery, expectations, and credibility risks. Policymakers should avoid overcommitting to low-rate assumptions and be willing to tighten before inflation becomes entrenched.