Extra doublets - Global analyses of Standard Model extensions in the fermionic or scalar sector

I present comprehensive analyses of the viable parameter regions of the Standard Model of particle physics and two of its extensions: the Standard Model with four fermion generations and the Two-Higgs-Doublets model of type II. Applying frequentist methods, I have performed global fits which show that the Standard Model is compatible with electroweak precision data and the measured Higgs signal strengths. The Standard Model with four generations is excluded by the experimental results with a p-value corresponding to more than five standard deviations. In the Two-Higgs-Doublets model of type II, the fit prefers the decoupling limit where it mimics the Standard Model; however, neutral heavy Higgs boson masses below 200 GeV are still allowed.