New Keynesian

The New Keynesian program is the synthesis that emerged through the late 1980s and 1990s as the operational successor to both the Old Keynesian tradition and the New Classical program. It accepts the New Classical methodological apparatus — rational expectations, microfoundations, intertemporal optimisation, equilibrium analysis — and rejects the New Classical strong claim that markets clear continuously. Instead, it shows that explicit nominal frictions (sticky prices via menu costs, Calvo or Rotemberg adjustment; sticky wages; financial-market imperfections) generate persistent real effects of monetary policy within an otherwise New Classical framework. The result is a tradition that looks Keynesian in its policy implications and New Classical in its tools — and is, by the early 2000s, the operating framework of the Federal Reserve, the European Central Bank, the Bank of England, and most other major central banks.

Thesis

Markets do not clear continuously. Nominal frictions — menu costs of price adjustment, staggered wage contracts, information processing constraints, financial-market imperfections — produce sticky prices and wages over horizons relevant to the business cycle. Within a fully optimising, rational-expectations general-equilibrium model, these frictions imply that monetary policy has real effects in the short run, that aggregate demand matters for output and employment, and that an active stabilisation policy can improve welfare. The Phillips Curve is forward-looking and conditional on the central bank’s regime; the natural rate is real but estimable only conditional on a policy rule. Central banks should commit to systematic feedback rules — the Taylor rule and its descendants — and the institutional architecture should support central-bank independence, transparent communication, and inflation targets.

Lead proponents

• N. Gregory Mankiw — early-career menu-costs work (1985, “Small Menu Costs and Large Business Cycles”) was foundational; later work on price-setting, taxation, and the intermediate-textbook market.

• Olivier Blanchard — Lectures on Macroeconomics (1989, with Stanley Fischer) was the principal graduate textbook bridging Old Keynesian and New Keynesian frameworks. Long career at MIT; chief economist of the IMF 2008–2015. The most institutionally consequential single voice in the tradition.

• David Romer — Advanced Macroeconomics (1996, multiple editions) is the standard graduate text in the field. With Mankiw, edited the two-volume New Keynesian Economics (1991), the canonical anthology of the early program.

• George Akerlof and Janet Yellen — near-rationality and efficiency-wage contributions to the foundations of price/wage stickiness. Yellen’s later policy career as Fed Chair (2014–2018) and Treasury Secretary (2021–2025) made her the principal New Keynesian central-banker of the era.

• Michael Woodford — Interest and Prices (2003) is the canonical theoretical treatment of monetary policy without money — the framework in which inflation expectations are anchored by interest-rate rules without reference to monetary aggregates.

• Jordi Galí — Monetary Policy, Inflation, and the Business Cycle (2008, multiple editions) is the standard graduate text on the New Keynesian DSGE framework specifically.

• Ben Bernanke and Mark Gertler — the financial-accelerator program (1989, 1995, 1999) extends NK frameworks into financial-system mechanics. Bernanke’s Fed Chairmanship (2006–2014) was the highest-profile real-time application of the framework, including its limitations.

• Lawrence Christiano, Martin Eichenbaum, Charles Evans — the Christiano-Eichenbaum-Evans (CEE 2005) DSGE specification became the workhorse model of central-bank research departments.

Key arguments

1. Nominal frictions matter and can be microfounded. Menu costs of price adjustment (Mankiw 1985; Akerlof-Yellen 1985), Calvo (1983) random-arrival pricing, or Rotemberg (1982) quadratic adjustment costs each produce sticky prices in an optimising framework. The aggregate consequence is a forward-looking Phillips Curve in which inflation depends on expected future inflation and the current output gap.

2. The 3-equation model. A New Keynesian Phillips Curve, an Euler-equation IS curve (consumption smoothing under intertemporal optimisation), and a Taylor-rule reaction function for the central bank produce a tractable model that captures the key dynamics: monetary policy moves real interest rates, real interest rates affect aggregate demand, demand affects output and inflation through the Phillips Curve, the central bank responds to inflation and the output gap.

3. Monetary policy works through real interest rates. With sticky prices, nominal interest-rate movements translate into real-rate movements that affect intertemporal consumption decisions. The transmission is real-rate-driven, not money-supply-driven; the framework operates without money in a meaningful sense (though it can be appended).

4. Central banks should commit to systematic rules. The Taylor rule (1993) — set the policy rate as a function of inflation deviations and the output gap — is the canonical formulation. Time-inconsistency arguments (Kydland-Prescott 1977) ground the case for rule-based independence; rational-expectations arguments ground the case for transparency.

5. Inflation targets anchor expectations. Explicit numerical inflation targets (introduced first by New Zealand in 1990, adopted by most major central banks by the early 2000s) anchor inflation expectations through commitment. The mechanism: rational agents forming expectations conditional on the central bank’s stated objective produce a Phillips Curve that shifts toward the target.

Key evidence

• The Great Moderation (1985–2007). A sustained period of low inflation, low output volatility, and successful disinflation across major economies. Widely interpreted at the time as a vindication of the New Keynesian framework — particularly its claims about credible-rule-based central banking.

• Empirical Phillips Curves. New-Keynesian Phillips Curves estimated over the 1990s and 2000s fit reasonably well, with forward-looking expectations and sticky-price coefficients within the ranges the framework predicts.

• DSGE models in central banks. By the mid-2000s, every major central-bank research department had a workhorse New Keynesian DSGE model. The Federal Reserve’s FRB/US, the ECB’s NAWM, the Bank of England’s COMPASS — these are New Keynesian models in essential structure.

• Inflation-targeting performance. Inflation targeting countries did achieve stable, low inflation through the 2000s, with measured improvements in inflation-expectation anchoring relative to non-targeting comparators.

Major critiques

• Zero-lower-bound performance, 2008–2020. When policy rates hit zero and could go no further conventionally, the framework’s monetary-transmission mechanism stopped operating in its baseline form. Quantitative easing and forward guidance were retrofitted into the framework, but neither sat naturally in the 3-equation core. The decade-long failure of advanced economies to return to pre-crisis output trends suggested mechanisms the framework had not anticipated.

• 2021–2023 inflation prediction failures. Standard NK Phillips Curves in 2020–2021 forecast that the post-pandemic stimulus would produce moderate inflation that the central bank would smoothly stabilise. The actual path — a sharp inflation spike to 9 percent, partly reversed without recession by 2023 — fit neither the strong demand-driven account nor the supply-shock-only account well. The framework’s coefficients had to be substantially re-estimated; the methodological apparatus survived, but the model’s forecasting reliability was visibly damaged.

• Financial-system thinness. Pre-2008 NK models treated the financial system as a frictionless veil. The Bernanke-Gertler financial-accelerator program partly remedied this, but the post-2008 consensus is that the standard NK apparatus systematically underweights financial-system mechanics — leverage, fire sales, run-prone funding structures, the macro-prudential dimension.

• Post-Keynesian and heterodox objections. The Post-Keynesian critique that the framework treats money as a passive accommodative variable rather than as endogenously created by the banking system has gained empirical traction post-2008. Conflict-inflation accounts of 2021–2023 have similarly gained ground that the prior two decades had denied them.

• Microfoundations imperialism. Some critics — including some sympathetic to the Old Keynesian tradition — argue that the requirement that all aggregate behaviour be derived from optimising representative agents has produced models that are tractable at the cost of empirical content. The “DSGE problem” (Solow’s phrase) is the trade-off between methodological rigour and predictive performance.

Status today

The New Keynesian program is the operational framework of the Federal Reserve, the ECB, the Bank of England, the Bank of Japan, and most other major central banks; it is the substrate on which contemporary monetary-policy analysis is built. Its institutional dominance is undiminished. Its intellectual confidence has been substantially shaken by the 2008 crisis, the long zero-lower-bound period, and the 2021–2023 inflation episode. The current research frontier integrates financial-system mechanics, heterogeneous agents (the HANK program), and a more humble assessment of central-bank capability than the 1990s framework projected. The successor program is recognisably continuous with NK rather than a break from it; whether the continuity will hold or a more substantial break is forming remains, in the early 2020s, an open question.