That is, parametric statistics are preferable when continuous variables are available [ 19], while nonparametric methods could be applied to nominal variables.
Therefore, the requirement for mechanical ventilation or vasopressors may be preferable as a variable than the actual use of these procedures.
In particular, it is preferable to simply using variables that are assumed to be highly correlated with marginal tax rates, such as statutory tax rates, dummies which indicate whether a firm is reporting losses or trichotomous variables, such as those used in Byoun (2008) or Gropp (2002).
In a regression framework, a large dispersion of the explanatory variables is preferable.
To further improve the recognition performance, it is preferable to evaluate the variables' importance iteratively.
Therefore, in the context of small sample sizes, one might consider preferable to apply some variable selection procedure, but it seems crucial to adequately choose those variables to be included in the PS model.
Overall, however, the GARCH approach still seems to be preferable to the instrumental variable approach.
The problem of risk factor definition: In the choice of risk factors, it is preferable to include continuous variable scales rather than categorical binary ones because, in this way, the values will not be submitted to personal subjectivity.
We believe that it is preferable to use the exogenous variables to decrease the forecast errors.
So all cluster 6 countries Libya, equatorial Guinea, Seychelles and Gabon policies on PC3 variables are relatively preferable.
