The Preliminary Thesis Dissertation (PTD) contains first of all the working paper ”Housing cycles in Switzerland - a time-varying approach", which focuses on the interplay of house prices, demand and supply for housing, business cycle conditions and the mortgage rate in Switzerland. Second, an extended research proposal for an analysis of the heterogeneous effects of the ECB's public sector purchase programme (PSPP) will be presented. Finally, the PTD concludes with a research idea on the impact of the ECB's unconventional monetary policy on bank lending."