Recent advances in metallocene catalysts have created a rich set of structural variations for polyethylenes. Copolymers of unprecedented comonomer content and branching distribution have been commercialized. In this paper, we report progress in our laboratories in characterizing these parameters. For polymers of moderate to high crystallinity, differential scanning calorimetry (DSC) provided very good qualitative data, while temperature rising elution fractionation was more quantitative. However, when the crystallinity is low or near non-existent, a dynamic mechanical technique provided excellent quantitative data. A new method is introduced where the normalized beta relaxation linewidth is used to calculate the branching distribution. Good results for nearly totally amorphous polymers were obtained.