Re: [Gretl-users] ordered probit
On Wed, 7 Jan 2015, Riccardo (Jack) Lucchetti wrote:
On Wed, 7 Jan 2015, Allin Cottrell wrote:
> It should now be safe to pass a series with non-integral values as
> the dependent variable in ordered probit, provided it has been
> sucessfully marked as discrete.
Excuse me, I may be missing something, but I fail to see the logic
in this. In an ordered probit model, the support of the dependent
variable is supposed to be a sequence of increasing numbers, which
indicate increasing "degress of intensity" of a certain unobserved
variable, whose conditional mean is what we're trying to estimate.
Of course they could be any sequence, as long as it's increasing,
but I would guess that common sense dictates they should be
increasing _integers_ [...]
I see your point, but I seem to remember some discussion long ago when
some people (Sven?) argued that a "degree of intensity" discrete
variable might in practice be coded with round-ish fractions (e.g.
multiples of 0.5). Also, FWIW, Stata allows this in ordered probit.
(Plus there's a constraint implied by the condition that the dependent
variable be "successfully marked as discrete" -- you can't define any
old junk as a discrete variable.)
Maybe Peter could comment on the dependent variable in his case?
Allin