For verification of our synthetic sample, we study the temperature distribution of a small volume-limited sample of observed WDs (Holberg et al. 2002). We use a single indicator R₆₃₀₀: the number ratio of WDs with T_eff 6300 K over those with T_eff > 6300 K. After correcting for a residual incompleteness with cool WDs, we find R₆₃₀₀ of 0.68(±0.24), in good agreement with our WD population model which suggests R₆₃₀₀ = 0.77.

With a magnitude limit of B = 16.0, the synthetic sample reduces from ≈ 13700 to only ≈ 1350 WDs. We use this to test the completeness of the prospective SPY WD sample. In the fields covered, it will deliver about 80% of the WDs with d < 100 pc and B < 16.0. A more detailed account of our results is given by Schröder et al. 2004.