We examine the faint-end ( M _ { V } > +14 ) behavior of the disk white dwarf luminosity function using the 1 / V _ { max } method , but , for the first time , fully including the effects of realistic observational errors in the derived luminosity function .
We find that observational errors , mostly in the bolometric corrections and trigonometric parallaxes , play a major role in obliterating ( real or artificial ) small scale fluctuations in the luminosity function .
A better estimator of the true luminosity function seems to be the median over simulations , rather than the mean .
When using the latter , an age of 10 Gyr or older can not be ruled out from the sample of Leggett , Ruiz , and Bergeron ( 1998 ) .