Sticky Prices or Sticky Wages? An Equivalence Result
Florin Bilbiie, Mathias Trabandt
Review of Economics and Statistics,
forthcoming
Abstract
We show an equivalence result in the representative-agent New-Keynesian model after demand, wage-markup and correlated price-markup and TFP shocks: assuming sticky prices and flexible wages yields identical allocations for GDP, consumption, labor, inflation and interest rates to the opposite case—flexible prices and sticky wages. This equivalence arises with identical price and wage Phillips-curve slopes and generalizes to any slopes' pair whose sum and product are identical. Equilibrium profits and wages are, however, substantially different; equivalence breaks when these factor-distributional implications matter for aggregate allocations, e.g. in New-Keynesian models with heterogeneous agents, endogenous firm entry, and non-constant returns to scale.
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Climate Change Economics in Vietnam: Redefining Economic Impact
Christian Otto, Christoph Schult, Thomas Vogt
Energy Economics,
Vol. 160 (August),
2026
Abstract
Vietnam, a low middle-income economy, grapples with considerable climate impacts, primarily driven by heat waves, sea level rise, and tropical cyclones. Under ongoing global warming, these extreme weather events are projected to further intensify. We use a dynamic general equilibrium model to study economic transition dynamics from 2015 to 2100, accounting for heat-induced labor productivity losses, agricultural land loss from sea level rise, and residential property damage from tropical cyclones. We compare a Paris-compatible strong mitigation scenario where global warming is limited to well below 2 °C above preindustrial levels to a strong emission scenario where warming reaches 4–5 °C. We find that the impacts of climate change on output and investment are highly uncertain, with differences between the two emission scenarios remaining statistically insignificant until the end of the century, despite substantially higher climate forcing in the latter. By contrast, consumption losses are significantly larger under the high emission scenario. These negative impacts are primarily driven by heat-induced labor productivity losses, while TCs are the main source of uncertainty. Our findings highlight the need for analytical frameworks to capture the different channels through which climate and climate change affect economic development, rather than focusing mainly on output-related damage, as done in many existing studies.
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Transition Dynamics in Heterogeneous-agent Models and the Distributional Consequences of Taxation
Alexandra Gutsch, Christoph Schult
IWH Discussion Papers,
No. 7,
2026
Abstract
We study how idiosyncratic income risk shapes the aggregate and distributional effects of labor and capital income taxation in dynamic general equilibrium models. To this end, we compare a heterogeneous-agent (HA) model with uninsurable idiosyncratic labor productivity risk and a ten-representative-agent (TE) model in which households correspond to fixed wealth deciles without such risk. At the aggregate level, both models generate qualitatively similar responses; however, the HA model exhibits a smaller recessionary impact driven by precautionary savings behavior, which stabilizes investment. At the distributional level, the models differ sharply. In the HA framework, tax shocks trigger endogenous mobility across wealth deciles. These inter-decile transition dynamics tend to benefit lower deciles. In contrast, the TA model features fixed household positions. Our findings highlight that while simpler multi-representative-agent models can approximate aggregate dynamics well, they may miss important distributional adjustment channels. The relevance of these mechanisms ultimately depends on the empirical importance of mobility across the wealth distribution, pointing to a key trade-off between model simplicity and accuracy.
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Climate Change Economics in Vietnam: Redefining Economic Impact
Christian Otto, Christoph Schult, Thomas Vogt
Abstract
Vietnam, a lower-middle-income economy, faces severe climate risks from heat waves, sea-level rise, and tropical cyclones, which are expected to intensify under ongoing global warming. Using a dynamic general equilibrium model, we analyze economic transition dynamics from 2015 to 2100, incorporating heat-induced labor productivity losses, agricultural land loss, and cyclone-related property damage. We compare a Paris-compatible scenario limiting warming to below 2 °C with a high-emission scenario reaching 4–5 °C. While output and investment impacts remain highly uncertain and statistically indistinguishable across scenarios until 2100, consumption losses are significantly larger under high emissions, mainly driven by heat-related productivity declines, with cyclones contributing most to uncertainty. These findings underscore the importance of considering multiple impact channels beyond output damages in climate-development research.
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Department Profiles
Research Profiles of the IWH Departments All doctoral students are allocated to one of the four research departments (Financial Markets – Laws, Regulations and Factor Markets –…
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Alumni
Alumni IWH provides guidance and support in job placement after graduation, including letters of recommendation and career advice. Graduates have found placements in academia…
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Academic conference on the 30th anniversary of the single market
Academic conference on the 30th anniversary of the single market 1st session Chair: Josefina Monteagudo (European Commission) The “completeness” of the EU single market in…
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Climate-resilient Economic Development in Vietnam: Insights from a Dynamic General Equilibrium Analysis (DGE-CRED)
Andrej Drygalla, Katja Heinisch, Christoph Schult
IWH Technical Reports,
No. 1,
2024
Abstract
In a multi-sector and multi-region framework, this paper employs a dynamic general equilibrium model to analyze climate-resilient economic development (DGE-CRED) in Vietnam. We calibrate sector and region-specific damage functions and quantify climate variable impacts on productivity and capital formation for various shared socioeconomic pathways (SSPs 119, 245, and 585). Our results based on simulations and cost-benefit analyses reveal a projected 5 percent reduction in annual GDP by 2050 in the SSP 245 scenario. Adaptation measures for the dyke system are crucial to mitigate the consumption gap, but they alone cannot sufficiently address it. Climate-induced damages to agriculture and labor productivity are the primary drivers of consumption reductions, underscoring the need for focused adaptation measures in the agricultural sector and strategies to reduce labor intensity as vital policy considerations for Vietnam’s response to climate change.
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Optimal Monetary Policy in a Two-sector Environmental DSGE Model
Oliver Holtemöller, Alessandro Sardone
IWH Discussion Papers,
No. 18,
2024
Abstract
In this paper, we discuss how environmental damage and emission reduction policies affect the conduct of monetary policy in a two-sector (clean and dirty) dynamic stochastic general equilibrium model. In particular, we examine the optimal response of the interest rate to changes in sectoral inflation due to standard supply shocks, conditional on a given environmental policy. We then compare the performance of a nonstandard monetary rule with sectoral inflation targets to that of a standard Taylor rule. Our main results are as follows: first, the optimal monetary policy is affected by the existence of environmental policy (carbon taxation), as this introduces a distortion in the relative price level between the clean and dirty sectors. Second, compared with a standard Taylor rule targeting aggregate inflation, a monetary policy rule with asymmetric responses to sector-specific inflation allows for reduced volatility in the inflation gap, output gap, and emissions. Third, a nonstandard monetary policy rule allows for a higher level of welfare, so the two goals of welfare maximization and emission minimization can be aligned.
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Is Risk the Fuel of the Business Cycle? Financial Frictions and Oil Market Disturbances
Christoph Schult
IWH Discussion Papers,
No. 4,
2024
Abstract
I estimate a dynamic stochastic general equilibrium (DSGE) model for the United States that incorporates oil market shocks and risk shocks working through credit market frictions. The findings of this analysis indicate that risk shocks play a crucial role during the Great Recession and the Dot-Com bubble but not during other economic downturns. Credit market frictions do not amplify persistent oil market shocks. This result holds as long as entry and exit rates of entrepreneurs are independent of the business cycle.
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