Research
My research focusses on using data and modern empirical methods to contribute to a better understanding of the past and present economic development, while aiming to shape the future by translating my academic findings into public policy recommendations. Specifically, I work on using machine learning to enhance our comprehension of economic history and apply economic complexity methods to develop insights for today’s societal challenges.
Here, you will find a list of my recent working papers and peer-reviewed publications in academic journals. Also, I contributed to several policy papers and reports over the past years (mostly in german) covering various topics such as free trade and global value chains, housing policy and competitiveness - a list of selected papers is provided in my CV.
Working Paper
The Growth, Geography, and Implications of Trade in Digital Products
Viktor Stojkoski, Philipp Koch, Eva Coll & César A. Hidalgo (2023). arXiv: 2310.02253.
Despite global efforts to harmonize international trade statistics, our understanding about trade in digital products and its implications remains elusive. Here, we study five key aspects of trade in digital products by introducing a novel dataset on the exports and imports of digital products. First, we show that compared to trade in physical goods, the origin of digital products exports is more spatially concentrated. Second, we show that between 2016 and 2021 trade in digital products grew faster than physical trade, at an annualized growth rate of 20% compared to 6% for physical trade. Third, we show that trade in digital products is large enough to partly offset some important trade balance estimates, like the physical trade deficit of the United States. Fourth, we show that countries that have decoupled economic growth from greenhouse gas emissions have larger and faster growing exports in digital product sectors. Finally, we add digital products to measures of economic complexity, showing that digital products tend to rank high in terms of sophistication contributing positively to the complexity of digital exporters. These findings provide a novel lens to understand the impact of the digital sector in the evolving geography of global trade.
Quadrupling historical GDP per capita estimates through machine learning
Philipp Koch, Viktor Stojkoski & César A. Hidalgo (2024)
Can we use data on the biographies of hundreds of thousands of historical figures to estimate the GDP per capita of countries and regions? Here we introduce a machine learning method to estimate the GDP per capita of dozens of countries and hundreds of regions in Europe and North America for the past 700 years starting from data on the places of birth, death, and occupations of hundreds of thousands of historical figures. We build an elastic net regression model to perform feature selection and generate out-of-sample estimates that explain 85% of the variance in known historical GDPs per capita. We use this model to generate GDP per capita estimates for countries, regions, and time periods for which this data is not available and validate them by comparing them with three proxies of economic output: body height in the 18th century, wellbeing in 1850, and church building activity in the 14th and 15th century. Additionally, we show our estimates reproduce the well-known reversal of fortune between southwestern and northwestern Europe between 1300 and 1800. These findings validate the use of fine-grained biographical data as a method to produce historical GDP per capita estimates. We publish our estimates with appropriate confidence intervals together with all collected source data in a comprehensive dataset.
Working paper available upon request
Publications (peer-reviewed)
The Role of Immigrants, Emigrants, and Locals in the Historical Formation of European Knowledge Agglomerations
Philipp Koch, Viktor Stojkoski & César A. Hidalgo (2023). Regional Studies.
Did migrants help make Paris a Mecca for the arts and Vienna a beacon of classical music? Or was their rise a pure consequence of local actors? Here, we use data more than 22,000 famous historical individuals born between the years 1000 and 2000 to estimate the contribution of famous immigrants, emigrants, and locals to the knowledge specializations of European regions. We find that the probability that a region develops a specialization in a new activity (physics, philosophy, painting, etc.) grows with the presence of immigrants with knowledge on that activity and related activities, while the opposite holds for loosing existing specializations. In contrast, we do not find robust evidence that locals with related knowledge play a statistically significant role in entries or exits. We address some of the endogeneity concerns using highly restrictive fixed-effects models considering any location-period-activity specific factors (e.g. the presence of a new university attracting scientists).
Multidimensional economic complexity and inclusive green growth
Viktor Stojkoski, Philipp Koch & César A. Hidalgo (2023). Communications Earth & Environment, 4, 130.
To achieve inclusive green growth, countries need to consider a multiplicity of economic, social, and environmental factors. These are often captured by metrics of economic complexity derived from the geography of trade, thus missing key information on innovative activities. To bridge this gap, we combine trade data with data on patent applications and research publications to build models that significantly and robustly improve the ability of economic complexity metrics to explain international variations in inclusive green growth. We show that measures of complexity built on trade and patent data combine to explain future economic growth and income inequality and that countries that score high in all three metrics tend to exhibit lower emission intensities. These findings illustrate how the geography of trade, technology, and research combine to explain inclusive green growth.
Park & Ride facilities and suburban sprawl
Wolfgang Schwarzbauer, Philipp Koch, Martin Wolf (2022). European Planning Studies, 30:7, 1378-1398.
Economic complexity and growth: Can value-added exports better explain the link?
Philipp Koch (2021). Economics Letters, 198, 109682.
Yet another space: Why the Industry Space adds value to the understanding of structural change and economic development
Philipp Koch & Wolfgang Schwarzbauer (2021). Structural Change and Economic Dynamics, 59, 198-213.