Despite their importance, the discussion of spillover effects in empirical research often misses the rigor dedicated to endogeneity concerns. We analyze a broad set of workhorse models of firm interactions and show that spillovers naturally arise in many corporate finance settings. This has important implications for the estimation of treatment effects: i) even with random treatment, spillovers lead to a complicated bias, ii) fixed effects can exacerbate the spillover-induced bias. We propose simple diagnostic tools for empirical researchers and illustrate our guidance in an application.

My dissertation consists of three studies, all viewing aggregate productivity as driven by the individual decisions of firms and the inventors that work for them. I use microeconometric analysis to study why firms innovate and economic theory to link these decisions to macroeconomic outcomes. The first paper in this dissertation studies how German manufacturing firms adjust their productivity in response to an increase in competition from foreign markets. German firms only increase their productivity if their new competitors come from other industrialized economies. This productivity increase is not driven by innovation. Instead, firms cut input expenses and prices while maintaining their output. The second paper traces the matching decisions of firms and inventors on the labor markets of developed economies. It adapts empirical techniques used in labor economics to this special segment of the labor market and shows that assortative matching has been increasing from 1974 to 2012: High quality inventors go to high quality firms more often than was the case in previous decades. This cannot be explained by changes in the patent invention function: The productivity of a match between a firm and an inventor of constant quality remains roughly unchanged. The third paper develops an endogenous growth model with inventor labor markets and two types of innovation: disruptive inventions that change the underlying technology of firms’ products and incremental improvements over existing products. Firms acquire expertise in certain technologies by hiring the inventors who are experts in these fields. This gives them a strong incentive to prevent disruptive inventions: If the underlying technology changes, their investment in these inventors becomes worthless. Large firms inhibit aggregate growth by poaching inventors from firms engaged in disruptive innovation.

Laut Volkswirtschaftlicher Gesamtrechnung erreicht die ostdeutsche Wirtschaft auch 30 Jahre nach dem Fall des Eisernen Vorhangs nur 80 % der westdeutschen Arbeitsproduktivität. Dieser Unterschied in der gesamtwirtschaftlichen Arbeitsproduktivität geht Hand in Hand mit vielen der wirtschaftlichen und gesellschaftlichen Probleme, denen Ostdeutschland heute gegenübersteht. Um die Ursachen des aggregierten Produktivitätsgefälles zu verstehen, wird die neuere Literatur zum Ost-West-Gefälle diskutiert, die granulare Daten auf Firmen- und Produktebene verwendet. Die Evidenz zeigt die Relevanz von Produktivitätsunterschieden auf Firmenebene für die aggregierte Lücke deutlich und stellt gängige Hypothesen infrage, die aus aggregierten Daten abgeleitet werden.

Using replacement matching on the basis of a statistical distance function we try to answer the question of whether subsidized vocational training is related to a negative image effect for the graduates. The results show that young people with equal qualifications acquired during subsidized vocational training are disadvantaged solely due to the kind of education they have received. The probability of finding adequate employment is lower than in the control group. Besides the 'general effect' of support we also find less favorable job opportunities for those who attended 'external' as compared to 'workplace-related' training.