Olivier Blanchard on four decades of macroeconomic theory
In this paper, Olivier Blanchard analyzes the trajectory of macroeconomic theory since the 1980s. Below is a summary of his key arguments:
Substantial convergence in methodology and architecture
- Methodology: Mainstream macroeconomics has adopted explicit micro foundations (optimizing agents) while allowing deviations from strict rational expectations and neoclassical utility maximization. Empirical methods now blend structural models, VARs, and micro-data analysis.
- Architecture: The field coalesced around nominal rigidities (e.g., sticky prices/wages) as a core distortion. New Keynesian (NK) and DSGE models became the dominant framework, integrating demand/supply shocks and policy rules.
Mechanisms and shock analysis
- Shocks: Both demand-side (e.g., fiscal policy, sentiment shifts) and supply-side (e.g., technological, geopolitical) shocks are recognized as drivers of fluctuations. However, the exact nature of these shocks remains debated.
- Transmission channels: Monetary policy’s role in stabilizing economies is widely accepted, though the specific mechanisms (e.g., credit vs. interest rate channels) lack full consensus.
Critiques and unresolved issues
- Overemphasis on general equilibrium: Blanchard critiques the pressure to force all analyses into general equilibrium frameworks prematurely, advocating for more partial equilibrium studies of specific mechanisms first.
- Nominal rigidities as a “crutch”: While essential for explaining demand-driven fluctuations, the reliance on nominal rigidities (e.g., Calvo pricing) is seen as a pragmatic but imperfect solution.
- Neglect of the medium run: Research bifurcates into short-run fluctuations and long-run growth, leaving medium-term issues (e.g., hysteresis, inequality) underexplored.
Progress and future directions
- Modular framework: The “core-plus-distortions” structure allows incremental improvements (e.g., adding heterogeneity or behavioral elements) without overhauling foundational models.
- Policy impact: DSGE models revolutionized central banking and inflation targeting, though their real-world predictive power remains limited.
- Call for interdisciplinary integration: Blanchard highlights the need to incorporate insights from behavioral economics, political economy, and network theory to address complex phenomena like financial crises or tariff wars.
Convergence? Thoughts about the evolution of mainstream macroeconomics over the last 40 years
Author: Olivier Blanchard
From: Peterson Institute for International Economics
Robert Barro on empirical macroeconomics
In a recent interview organized by the Hoover Institute, Robert Barro shared his thoughts on fiscal multipliers, inflation, and the value of empirical macroeconomics.
Government spending multipliers
- Barro argues that, based on empirical evidence (especially from U.S. military spending), the multiplier is typically between zero and one. This means that each dollar of government spending increases output by less than one dollar, with Barro’s research suggesting a typical multiplier around 0.5.
- Barro is skeptical of claims that the multiplier exceeds one, stating that such results are “completely ridiculous” outside of extraordinary circumstances. He emphasizes that the correct baseline for the multiplier is zero, not one.
Inflation and government debt
- He notes that recent large increases in government spending (such as pandemic-era transfer payments) were largely paid for through surprise inflation, which reduced the burden of outstanding government bonds by as much as 10–15% of GDP.
- While he criticizes the scale of recent fiscal expansions (especially under Biden), Barro suggests that paying for them via inflation may not have been as irrational as some critics claim, given the alternatives would also have been costly.
Empirical methods in growth economics
- Barro defends the use of cross-country regressions to study long-run economic growth, arguing that they remain valuable for understanding how policies and institutions (like property rights, education, and fertility) affect growth.
- He acknowledges the limitations of these methods-particularly issues of endogeneity and imperfect identification-but contends that dismissing cross-country data entirely is a mistake, as natural experiments are rare in macroeconomics.
- Barro expresses concern that the current trend in economics, which prioritizes causal identification over broad correlation studies, risks ignoring valuable insights from the best available data.
Broader context
Barro’s perspective is that macroeconomic research should balance the quest for clear causality with the practical need to use the richest data sources available, even if they come with methodological challenges.
Interview with Robert Barro: Empirical Macroeconomics
By: Timothy Taylor – Journal of Economic Perspectives
