What correlation should I run?


Fortran must die
Or possibly polychoric correlations if your software supports that and you feel there is a latent variable behind the ordinal measurements you are using.


Less is more. Stay pure. Stay poor.

Please explain this statement in more detail, " latent variable behind the ordinal measurements". Why might that need to be present?


Fortran must die
Because polychoric correlations assumes that behind the observed measurement there is a continuous latent factor. If there is not it is not valid to use polychoric/tetronic correlations (although in practice I suspect that is ignored).