Visual comparison of our dynamical WD mass for YY Dra (shaded column, 1 σ) with previous estimates derived from spectral modelling of: RXTE hard X-ray data (labelled in the figure as 1; Suleimanov et al. 2005), Swift hard X-ray data (labelled as 2 and 5; Brunschweiger et al. 2009 and Suleimanov et al. 2019) and Suzaku hard X-ray data (labelled as 3 and 4; Yuasa et al. 2010 and Xu et al. 2019). We also include one estimate based on the ratio of the iron emission lines in Suzaku spectroscopy (labelled as 6; Xu et al. 2019).