Smooth and Persistent Forecasts of German GDP: Balancing Accuracy and Stability
Katja Heinisch, Simon van Norden, Marc Wildi
IWH Discussion Papers,
No. 1,
2026
Abstract
Forecasts that minimize mean squared forecast error (MSE) often exhibit excessive volatility, limiting their practical applicability. We address this accuracy-smoothness trade-off by introducing a Multivariate Smooth Sign Accuracy (M-SSA) framework, which extracts smoothed components from leading indicators to enhance the signal-to-noise ratio and control the forecast volatility and timing. Applied to quarterly German GDP growth, our method yields smoothed forecasts that can improve forecasting accuracy, particularly over medium-term horizons. We find that while smoother forecasts tend to lag slightly around turning points, this can be offset by adjusting the forecast horizon. These findings highlight the practicality of the M-SSA framework for both forecasters and policymakers, especially in settings where forecast revisions or policy adjustments are costly.
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Employment Responses to Increased Biodiversity Transition Risk
Duc Duy Nguyen, Huyen Nguyen, Trang Nguyen, Vathunyoo Sila
IWH Discussion Papers,
No. 20,
2025
Abstract
This paper examines how firms adjust the number and types of workers they hire in response to increased biodiversity transition risk. Using the adoption of the Key Biodiversity Areas Standard of 2016 as a source of variation that increases the risk of future land-use restrictions, we find that firms reduce job postings in affected areas and reallocate labor to less exposed regions. This effect is concentrated among firms that make negative impacts on biodiversity. Cuts are stronger among production roles, while hiring in green and adaptive occupations increases. The effect is not driven by changes in capital investment or workers’ labor supply decisions. Our findings contribute to the ongoing debate on the costs and benefits of biodiversity conservation policies and their implications for labor market outcomes.
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The Health Costs of Losing Political Representation: Evidence From U.S. Presidential Elections
Sris Chatterjee, Iftekhar Hasan, Stefano Manfredonia
Plos One,
Vol. 20 (10),
2025
Abstract
We investigate whether a change in political leadership affects health outcomes. To do so, we exploit turnover elections that move partisan individuals into and out of alignment with the party of the President. We document that the lack of political alignment has a negative, immediate, and long-lasting effect on health. We do not find any evidence that our results can be explained by other confounding trends or by changes in economic outcomes or other economic policies. Further results suggest that political sentiments and social isolation are important potential mechanisms in this setting and that lack of political representation affects the mental health of individuals.
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Road to Net Zero: Carbon Policy and Redistributional Dynamics in the Green Transition
Alessandro Sardone
IWH Discussion Papers,
No. 16,
2025
Abstract
This paper examines the macroeconomic and distributional effects of the European Union’s transition to Net Zero emissions through a gradually increasing carbon tax. I develop a New Keynesian Environmental DSGE model with two household types and distinct energy and non-energy sectors. Five alternative uses of carbon tax revenues are considered: equal transfers to households, targeted transfers to Hand-to-Mouth households, subsidies to green energy firms, and reductions in labor and capital income taxes. In the absence of technological progress, the carbon tax policy induces a persistent increase in energy prices and a reduction in GDP, investment, and consumption. Headline inflation falls below zero in the medium run, reflecting weaker aggregate demand. Distributional outcomes vary significantly depending on the implemented revenue recycling scheme: targeted transfers are the most progressive but entail larger macroeconomic costs, while subsidies and tax cuts mitigate output and investment losses but are less effective in narrowing the consumption gap. A limited foresight scenario, in which agents learn about policy targets sequentially, generates more volatile adjustment paths and temporary inflationary spikes around announcements, but long-run outcomes remain close to the baseline.
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Climate Risks and Debt Structure
Bill Francis, Iftekhar Hasan, Chunxia Jiang, Zenu Sharma, Yun Zhu
British Accounting Review,
Vol. 57 (5),
2025
Abstract
This paper examines the impact of climate risks on the debt structure of a sample of U.S. firms from 2002 through 2020. Climate risks—mainly physical, regulatory, and transition risks—are associated with a concentrated debt structure for the affected firms. However, when climate risks propagate through the channels of expected bankruptcy costs and sustainability, they are associated with a more diversified debt structure. Additionally, climate risks asymmetrically impact the relationship between access to finance and debt structure. Results from a quasi-natural experiment reaffirm the impact of climate risks on debt structure.
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Within-Country Inequality and the Shaping of a Just Global Climate Policy
Marie Young-Brun, Francis Dennig, Frank Errickson, Simon Feindt, Aurélie Méjean, Stéphane Zuber
Proceedings of the National Academy of Sciences of the United States of America (PNAS),
Vol. 122 (39),
2025
Abstract
Climate policy design must balance emissions mitigation with concerns for fairness, particularly as climate change disproportionately affects the poorest households within and across countries. Integrated Assessment Models used for global climate policy evaluation have so far typically not considered inequality effects within countries. To fill this gap, we develop a global Integrated Assessment Model representing national economies and subnational income, mitigation cost, and climate damage distribution and assess a range of climate policy schemes with varying levels of effort sharing across countries and households. The schemes are consistent with limiting temperature increases to 2 °C and account for the possibility to use carbon tax revenues to address distributional effects within and between countries. We find that carbon taxation with redistribution improves global welfare and reduces inequality, with the most substantial gains achieved under uniform taxation paired with global per capita transfers. A Loss and Damage mechanism offers significant welfare improvements in vulnerable countries while requiring only a modest share of global carbon revenues in the medium term. The poorest households within all countries may benefit from the transfer scheme, in particular when some redistribution is made at the country level. Our findings underscore the potential for climate policy to advance both environmental and social goals, provided revenue recycling mechanisms are effectively implemented. In particular, they demonstrate the feasibility of a welfare improving global climate policy involving limited international redistribution.
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Political Preferences Through Stages of the COVID-19 Pandemic
Alena Bičáková, Štěpán Jurajda
Political Research Quarterly,
Vol. 78 (3),
2025
Abstract
How durable are the political accountability effects of the worst pandemic in a century? We track the effects of the COVID-19 pandemic on political preferences through its “high” and “low” phases in the Czech Republic. Uniquely, we ask about the effects of both the health and the economic costs of the pandemic measured at both personal and municipality levels. Consistent with the literature, we estimate effects suggestive of political accountability of leaders during “high” pandemic phases without higher support for non-democratic alternatives. However, we also find that the pandemic political accountability effects are mostly short-lived, and do not extend to the first post-pandemic elections.
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How Do Banks Respond to Supplier IPOs?
Sung C. Bae, Iftekhar Hasan, Liuling Liu, Haizhi Wang
Financial Markets, Institutions and Instruments,
Vol. 34 (3),
2025
Abstract
This paper examines how supplier IPO events affect their key customers’ cost of debt. The evidence reveals that average loan spreads for customers increase by roughly 20% (23.7 basis points) following suppliers’ IPO events. This negative spillover effect is more pronounced when suppliers make significant relationship-specific investments (high switching cost), when suppliers face less concentrated customer bases, or when customers face more concentrated supplier bases. Our results show that customers receive less favourable trade terms and are forced to pay more for inputs after their suppliers go public, all of which increase customers’ operational costs, risk and subsequent borrowing costs. Furthermore, we document that customer loan contracts become significantly more restrictive after a supplier's IPO. Finally, we find that the observed negative spillover effect is also present in customers’ access to the public bond market.
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Halle Institute for Economic Research
Rents in Europe’s cities are 23% higher on average than in rural areas The latest European Real Estate Index (EREI) by the Halle Institute for Economic Research (IWH) shows that…
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Policy Output
Reports › CompNet’s flagship and special reports provide in-depth, data-driven analysis on productivity, competitiveness, and related economic trends, using the latest CompNet…
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