Econometric Tools for Macroeconomic Forecasting and Simulation

This group conducts research on quantitative macroeconomic and time-series models, with a focus on forecasting, economic fluctuations and policy evaluation. Research in this group contributes to the econometric foundation of IWH‘s macroeconomic analyses and forecasts, enhancing their accuracy.

The group develops tailored forecasting tools and conducts applied research within third-party funded projects. Recent collaborations include model development for Volkswagen Bank and economic and finance ministries in Asia (supported by GIZ). The group has contributed to the EU Horizon 2020 project ENTRANCES by developing quantitative models to assess the economic and distributional impacts of coal phase-out policies and broader clean energy transitions across European regions. The group contributes to the ongoing evaluation of the German Investment Act for Mining Regions.

Research Cluster
Economic Dynamics and Stability

Your contact

Dr Katja Heinisch
Dr Katja Heinisch
- Department Macroeconomics
Send Message +49 345 7753-836 LinkedIn profile

EXTERNAL FUNDING

07.2022 ‐ 12.2026

Evaluation of the InvKG and the federal STARK programme

German Federal Ministry for Economic Affairs and Climate Action

On behalf of the Federal Ministry of Economics and Climate Protection, the IWH and the RWI are evaluating the use of the approximately 40 billion euros the federal government is providing to support the coal phase-out regions..

See project page

12.2024 ‐ 02.2026

Macroeconomic Modelling for Energy Investments in Vietnam

Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH

Dr Katja Heinisch

08.2024 ‐ 03.2025

Strengthening Public Financial Management in Vietnam

Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH

Dr Katja Heinisch

01.2023 ‐ 01.2025

IWH Workshop on Forecasting in Times of Structural Change and Uncertainty

Deutsche Bundesbank

Dr Katja Heinisch

01.2023 ‐ 12.2023

Early determination of stable results for gross domestic product or real economic growth and gross value added at federal state level

Landesbetrieb Information und Technik Nordrhein-Westfalen

The project examines whether the accuracy of the first estimate of gross value added and gross domestic product for the federal states can be increased, thereby reducing the extent of subsequent revisions.

 See project page

Professor Dr Oliver Holtemöller

01.2018 ‐ 12.2023

EuropeAid (EU Framework Contract)

Europäische Kommission

Professor Dr Oliver Holtemöller

05.2020 ‐ 09.2023

ENTRANCES: Energy Transitions from Coal and Carbon: Effects on Societies

Europäische Kommission

ENTRANCES aims at examining the effects of the coal phase-out in Europe. How does the phase-out transform society – and what can politics do about it?

see project's webpage

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 883947.

Professor Dr Oliver Holtemöller
Dr Katja Heinisch

10.2019 ‐ 01.2023

Climate Resilient Economic Development

Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH

Climate change has a substantial impact on economic growth and a country’s development. This increases the need for reliable and viable approaches to assessing the impact of climate risks and potential adaptation scenarios. Political decision-makers in ministries of planning and economy need sound forecasts in order to design and finance adequate economic policy instruments and actively to take countermeasures. In the pilot countries (Georgia, Kazakhstan and Vietnam), climate risk is included in macroeconomic modelling, enabling the results to be integrated into the policy process so as to facilitate adapted economic planning. The IWH team is responsible for macroeconomic modelling in Vietnam.

see project's page on GIZ website

Dr Katja Heinisch

07.2016 ‐ 12.2018

Climate Protection and Coal Phaseout: Political Strategies and Measures up to 2030 and beyond

Dr Katja Heinisch

01.2017 ‐ 12.2017

Support to Sustainable Economic Development in Selected Regions of Uzbekistan

Dr Andrej Drygalla

01.2017 ‐ 12.2017

Short-term Macroeconomic Forecasting Model in Ministry of Economic Development and Trade of Ukraine

Dr Andrej Drygalla

01.2016 ‐ 12.2017

Development of analytical tools based on Input-Output table

The aim of the project was the development of an analytical tool to assess the gains and losses of possible state programs supporting the development of the private sector of the Tajik economy.

Dr Katja Heinisch

11.2015 ‐ 12.2016

Employment and Development in the Republic of Uzbekistan

Support to sustainable economic development in selected regions of Uzbekistan

Dr Katja Heinisch

05.2016 ‐ 05.2016

Framework and Finance for Private Sector Development in Tajikistan

Dr Katja Heinisch

02.2016 ‐ 04.2016

Macroeconomic Reforms and Green Growth - Assessment of economic modelling capacity in Vietnam

Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH

Dr Katja Heinisch

10.2015 ‐ 03.2016

Improved Evidence-based Policy Making - GIZ Tadschikistan

Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH

Dr Katja Heinisch

Refereed Publications

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Sticky Prices or Sticky Wages? An Equivalence Result

Florin Bilbiie Mathias Trabandt

in: 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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Transparency and Forecasting: The Impact of Conditioning Assumptions on Forecast Accuracy

Katja Heinisch Christoph Schult Carola Stapper

in: Applied Economic Letters, forthcoming

Abstract

This study investigates the impact of inaccurate assumptions on economic forecast precision. We construct a new dataset comprising an unbalanced panel of annual German GDP forecasts from various institutions, taking into account their underlying assumptions. We explicitly control for different forecast horizons to reflect the information available at the time of release. Our analysis reveals that approximately 75% of the variation in squared forecast errors can be attributed to the variation in squared errors of the initial assumptions. This finding emphasizes the importance of accurate assumptions in economic forecasting and suggests that forecasters should transparently disclose their assumptions to enhance the usefulness of their forecasts in shaping effective policy recommendations.

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The Effects of the Iberian Exception Mechanism on Wholesale Electricity Prices and Consumer Inflation: A Synthetic-controls Approach

Miguel Haro Ruiz Christoph Schult Christoph Wunder

in: Applied Economic Letters, forthcoming

Abstract

This study employs synthetic control methods to estimate the effect of the Iberian exception mechanism on wholesale electricity prices and consumer inflation, for both Spain and Portugal. We find that the intervention led to an average reduction of approximately 40% in the spot price of electricity between July 2022 and June 2023 in both Spain and Portugal. Regarding overall inflation, we observe notable differences between the two countries. In Spain, the intervention has an immediate effect, and results in an average decrease of 3.5 percentage points over the twelve months under consideration. In Portugal, however, the impact is small and generally close to zero. Different electricity market structures in each country are a plausible explanation.

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Step by Step ‒ A Quarterly Evaluation of EU Commission's GDP Forecasts

Katja Heinisch

in: Journal of Forecasting, Vol. 44 (3), 2025

Abstract

The European Commission’s growth forecasts play a crucial role in shaping policies and provide a benchmark for many (national) forecasters. The annual forecasts are built on quarterly estimates, which do not receive much attention and are hardly known. Therefore, this paper provides a comprehensive analysis of multi-period ahead quarterly GDP growth forecasts for the European Union (EU), euro area, and several EU member states with respect to first-release and current-release data. Forecast revisions and forecast errors are analyzed, and the results show that the forecasts are not systematically biased. However, GDP forecasts for several member states tend to be overestimated at short-time horizons. Furthermore, the final forecast revision in the current quarter is generally downward biased for almost all countries. Overall, the differences in mean forecast errors are minor when using real-time data or pseudo-real-time data and these differences do not significantly impact the overall assessment of the forecasts’ quality. Additionally, the forecast performance varies across countries, with smaller countries and Central and Eastern European countries (CEECs) experiencing larger forecast errors. The paper provides evidence that there is still potential for improvement in forecasting techniques both for nowcasts but also forecasts up to eight quarters ahead. In the latter case, the performance of the mean forecast tends to be superior for many countries.

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Regional Industrial Effects in Germany from a Potential Gas Deficit

Robert Lehmann Christoph Schult

in: German Economic Review, Vol. 25 (3), 2024

Abstract

We estimate potential regional industrial effects in case of a threatening gas deficit. For Germany, the reduction leads to a potential decrease in industrial value added by 1.6 %. The heterogeneity across German states is remarkable, ranging from 2.2 % for Rhineland-Palatinate to 0.7 % for Hamburg. We emphasize the need for regional input-output tables to conduct economic analysis on a sub-national level, particularly when regional industrial structures are heterogeneous. The approximation with national figures can lead to results that differ both in magnitude and relative regional exposure. Our findings highlight that more accurate policy guidance can be achieved by improving the regional database.

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Working Papers

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Transition Dynamics in Heterogeneous-agent Models and the Distributional Consequences of Taxation

Alexandra Gutsch Christoph Schult

in: 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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Growth Clubs and Regional Economic Convergence in Germany

Oliver Holtemöller Christoph Schult Anna Solms

in: IWH Discussion Papers, No. 4, 2026

Abstract

Many countries and regions remain below the level of economic activity of the world’s most advanced economies. Some countries form growth clubs, some are stuck in the middle-income trap, and some stay on a very low level of economic activity. Although this situation is well documented on the country level, there is less evidence at the sub-national level within countries. We estimate county-level capital stocks and price indices and provide a comprehensive county-level data set for Germany. We find no evidence of convergence across all counties even if we condition on important drivers of long-term growth such as physical and human capital accumulation. Instead, we identify five convergence clubs, using endogenous clustering. We analyze differences in growth paths and describe the identified clusters based on variations in contributions of capital, labor, and total factor productivity to economic growth. Additionally, we examine the role of migration for regional development and find that net migration has in particular contributed to growth in richer regions.

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Smooth and Persistent Forecasts of German GDP: Balancing Accuracy and Stability

Katja Heinisch Simon van Norden Marc Wildi

in: 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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Climate Change Economics in Vietnam: Redefining Economic Impact

Christian Otto Christoph Schult Thomas Vogt

in: IWH Discussion Papers, No. 15, 2025

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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Assumption Errors and Forecast Accuracy: A Partial Linear Instrumental Variable and Double Machine Learning Approach

Katja Heinisch Fabio Scaramella Christoph Schult

in: IWH Discussion Papers, No. 6, 2025

Abstract

Accurate macroeconomic forecasts are essential for effective policy decisions, yet their precision depends on the accuracy of the underlying assumptions. This paper examines the extent to which assumption errors affect forecast accuracy, introducing the average squared assumption error (ASAE) as a valid instrument to address endogeneity. Using double/debiased machine learning (DML) techniques and partial linear instrumental variable (PLIV) models, we analyze GDP growth forecasts for Germany, conditioning on key exogenous variables such as oil price, exchange rate, and world trade. We find that traditional ordinary least squares (OLS) techniques systematically underestimate the influence of assumption errors, particularly with respect to world trade, while DML effectively mitigates endogeneity, reduces multicollinearity, and captures nonlinearities in the data. However, the effect of oil price assumption errors on GDP forecast errors remains ambiguous. These results underscore the importance of advanced econometric tools to improve the evaluation of macroeconomic forecasts.

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