Understanding Gender Match Effects in Higher Education: The Role of Class Size
Stephan Maurer, Guido Schwerdt, Simon Wiederhold
Journal of Human Resources,
forthcoming
Abstract
It is widely believed that female students perform better when taught by female professors. However, little is known about the mechanisms explaining these gender match effects. Using administrative records from a German public university, which cover all programs and courses between 2006 and 2018, we show that gender match effects are sizable in smaller classes, but are absent in larger classes. These results suggest that direct and frequent interactions between students and professors are crucial for gender match effects to emerge. In contrast, the mere fact that one’s professor is female is not sufficient to increase performance of female students.
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28.09.2026 • 29/2026
East Germany also benefits from higher foreign demand – Implications of the Joint Economic Forecast Autumn 2026 and official regional data for the East German economy
In 2026, economic activity in East Germany is expected to grow significantly, though somewhat less strongly than in Germany as a whole. In the years ahead, the Halle Institute for Economic Research (IWH) forecasts only minor differences in growth rates between East and West Germany. The East German economy is expected to grow by 0.9% in the current year (Germany as a whole: 1.3%). Thereafter, output in East Germany is likely to expand at a pace broadly similar to that of Germany overall, rising by 0.9% in 2027 and by 0.4% in 2028.
Oliver Holtemöller
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24.09.2026 • 28/2026
Joint Economic Forecast Autumn 2026: Recovery under structural stress – fiscal policy on slippery ground
The German economy has been recovering since the end of 2025. This recovery, although stronger than expected in spring, remains modest. The leading economic research institutes expect GDP growth of 1.3% for the current year and 1.1% and 0.4% for the following two years, respectively. Compared with the spring forecast, the outlook for 2026 has been revised upward by 0.7 and that for 2027 by 0.2 percentage points. “The economy has developed more robustly than expected. However, the recovery rests on a narrow foundation, as high energy prices and structural problems continue to weigh on economic activity,” says Oliver Holtemöller, Head of Macroeconomic Forecasting at the Halle Institute for Economic Research (IWH). In the current quarter, low water levels are also temporarily dampening economic activity. The government deficit continues to increase, leading to a growing need for fiscal consolidation.
Oliver Holtemöller
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10.09.2026 • 27/2026
EREI-Update: Rents in Europe’s cities are 23% higher on average than in rural areas
The European Commission currently prepares the Affordable Housing Act to tackle widespread concerns about tight housing markets, for example voiced by the German Tenants' Federation (DMB) which blames rising rental cost as one main driver of a social crisis in Germany. The latest European Real Estate Index (EREI) by the Halle Institute for Economic Research (IWH) shows that rental prices in Germany rose indeed three times compared to the European average in August. Moreover, the rental premium in metropolitan areas vis-à-vis the average in non-metropolitan areas in eleven EU member states amounts to 23%.
Michael Koetter
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03.09.2026 • 25/2026
Economic Outlook: German economy on a recovery path – Tailwinds from the global economy and fiscal policy
An increase in foreign demand has put the German economy on a recovery path in the first half of the year, despite higher energy prices. In the coming quarters, rising public investment is expected to support economic activity. According to the autumn forecast of the Halle Institute for Economic Research (IWH), gross domestic product (GDP) is projected to grow by 1.4% this year and by 0.8% in 2027. Economic recovery in eastern Germany is expected to be somewhat weaker. In June, the IWH economists had predicted growth of 0.9% for both this and the next year.
Oliver Holtemöller
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Common Ownership and CEO Social Ties Across Portfolio Firms
Dennis Hutschenreiter, Qianshuo Liu
IWH Discussion Papers,
No. 9,
2026
Abstract
This paper examines whether common institutional ownership is associated with CEO connectedness across firms. We document that higher common ownership between two same-industry firms predicts a greater likelihood that a newly appointed CEO has preexisting social ties to the incumbent CEO of the peer firm. To address endogeneity, we use mergers among institutional investors in a stacked difference-in-differences design. In a hiring-firm-peer panel that carries connection status forward from the most recent appointment, exposure to a merger-induced common blockholder approximately doubles the probability that the pair is observed in a connected-CEO state. In a broader firm-pair panel, it increases the probability of CEO connections by 48.7%. We further document that gaining CEO connections through another firm’s CEO appointment is associated with improvements in peer firms’ returns on assets and Tobin’s Q, in both OLS and IV specifications. Peer firms that gain such a connection also experience positive abnormal returns around other firms’ CEO hiring announcements, corresponding to an average increase of $112.5 million in shareholder value. These performance patterns suggest that CEO connections may be valuable from a portfolio-level perspective. Consistent with this interpretation, the association between common ownership and CEO connections is concentrated among product-similar and organizationally complex firms and strengthens after the 2008–2009 financial crisis, when connections appear more valuable. Our findings point to CEO connection as a potential governance channel through which common institutional ownership is linked to firm outcomes, complementing prior work on executive compensation, shareholder voting, and board interlocks.
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11.06.2026 • 17/2026
Economic Outlook: Between Energy Crisis and AI Boom
Until the outbreak of the energy crisis, the German economy was on a path to recovery. Now the recovery will only continue over the course of 2026 if the Gulf conflict eases and energy prices do not rise further. This assumption underlies the present summer forecast of the Halle Institute for Economic Research (IWH). In that case, German output is expected to increase by 0.9% for this year and for 2027. Growth rates in East Germany will be similar. In March, the IWH economists had predicted growth of 0.7% for 2026 and 1% for the next year.
Oliver Holtemöller
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Individualism and the Formation of Human Capital
Katharina Hartinger, Sven Resnjanskij, Jens Ruhose, Simon Wiederhold
Journal of the European Economic Association,
Vol. 24 (3),
2026
Abstract
More individualistic countries experience higher economic growth. We provide evidence for a human-capital-based explanation of the growth effects of individualism. Using data from the largest international adult skill assessment, we establish that individualism shapes human capital formation. We identify the effects of individualism by exploiting variation between migrants at the origin-country, origin-language, and person level. Migrants from more individualistic cultures have higher cognitive skills and larger skill gains over time. They also invest more in their skills over the life cycle, as they acquire more years of schooling and are more likely to participate in adult education activities. Individualism is more important in explaining adult skill formation than any other cultural trait that previous literature has emphasized. In the labor market, more individualistic migrants earn higher wages and are less often unemployed. We show that our results cannot be explained by selective migration or omitted origin-country variables.
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Common Ownership, Tacit Know-How, and the Market for Technology
Dennis Hutschenreiter
IWH Discussion Papers,
No. 3,
2026
Abstract
Firms increasingly rely on markets for technology to acquire innovations developed outside their boundaries, yet acquiring intellectual property rights alone often does not guarantee successful implementation. Many technologies depend on tacit know-how that must be supplied by the provider after the transaction is completed. This paper examines whether common ownership between a technology provider and a potential adopter mitigates this implementation problem. I develop a model in which overlapping institutional investors cause the provider to partially internalize the adopter’s gains from successful implementation, strengthening incentives to transfer tacit know-how. This mechanism operates only when know-how is unverifiable – absent this friction, common ownership leaves matching and outcomes unchanged. Under moral hazard, the model predicts that common ownership increases the likelihood of technology transfer to a given adopter, that this effect is stronger when tacit know-how is more important, and that common ownership improves post-transfer outcomes conditional on adoption. I test these predictions using U.S. patent reassignments between publicly traded firms. Using within-deal variation across competing potential adopters and plausibly exogenous variation from passive index-fund holdings, I show that common ownership increases the likelihood that a firm acquires a technology, particularly when the transferred bundle is more tacit. Common ownership predicts stronger subsequent innovation and higher future firm value, especially when ownership overlap is concentrated among investors with stronger incentives to monitor the provider. These findings show how ownership structure shapes interfirm technology transfer by affecting not only who acquires a technology, but also how much value is created.
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01.04.2026 • 10/2026
Economic growth in East Germany slightly higher than in the West – Implications of the Joint Economic Forecast Spring 2026 and of new data for the East German economy
In 2025, the East German economy expanded by 0.4%, somewhat more than Germany as a whole (0.2%). For 2026, the Halle Institute for Economic Research (IWH) expects growth of 0.7% for East Germany (Germany: 0.6%). The unemployment rate is likely to amount to 7.9% in the current year, after 7.8% in 2025.
Oliver Holtemöller
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