  We present the current status of the W-boson mass averaging project, an
ongoing effort aimed at combining Tevatron and LHC measurements. Methods are
presented to accurately evaluate the effect of PDFs and other modelling
variations on existing measurements. Based on this approach, the measurements
can be corrected to a common modelling reference and to the same PDFs, and
subsequently combined accounting for PDF correlations in a quantitative way. We
discuss the combination procedure, and the impact of improvements in the
theoretical description of W-boson production and decay.
