First of all, I would like to thank my supervisor Klaus F. Zimmermann for his guidance, continuous support and valuable comments on my papers. I am also indebted to Katja Görlitz for immediately agreeing to be my second supervisor and lending her expertise from the field of empirical labor economics. A special thank goes to my co-author and mentor Thomas Siedler for our produc-tive and delightful cooperation. My work immensely gained from his enthusiasm and encouragement. Furthermore, I am grateful to Helmut Lütkepohl for being a wonderful employer. I wrote this thesis while being a doctoral student in the Graduate Center of DIW Berlin. This program’s academic training and stimulating research environment helped tremendously in completing t...