Understanding selection effects in observed samples of cataclysmic   variables
  Large differences between the properties of the known sample of cataclysmic variable stars (CVs) and the predictions of the theory of binary star evolution have long been recognised. However, because all existing CV samples suffer from strong selection effects, observational bias must be considered before it is possible to tell whether there is an inconsistency, which would imply a failure of the evolutionary model. We have modelled common selection effects and illustrate their influence on observed CV samples. 
Magaretha L. Pretorius, Christian Knigge, Ulrich Kolb