  Recently, Lee et al. used Gaussian mixture models (GMM) to study the radio
pulsar population. In the distribution of normal pulsars in the P-dotP plane,
they found four clusters. We develop this approach further and apply it to
different synthetic pulsar populations in order to determine whether the method
can effectively select groups of sources that are physically different. We
check several combinations of initial conditions as well as the models of
pulsar evolution and the selection effects. We find that in the case of rapidly
evolving objects, the GMM is oversensitive to parameter variations and does not
produce stable results. We conclude that the method does not help much to
identify the sub-populations with different initial parameters or/and
evolutionary paths. For the same reason, the GMM does not discriminate
effectively between theoretical population synthesis models of normal radio
pulsars.
