Re: [Gretl-devel] gretl bug: ordered probit model
On Mon, 9 Oct 2017, Allin Cottrell wrote:
On Mon, 9 Oct 2017, Riccardo (Jack) Lucchetti wrote:
> However, I was thinking: can lagging the constant ever make sense, in any
> situation? Shouldn't const(-1) be a no-op?
I suppose it could be used as a tricksy way of getting a series
that's all 1s apart from NA at observation 1. We could ban the
operation but I'm not sure that would be worthwhile.
Looking further into this, I see that we already flagged an error if
"const" was passed to the lags() function -- but, inconsistently, we
accepted it in simple form such as "const(-1)".
So now I've made it an error in either case, with a new error message,
"The constant cannot be lagged".
I think that's right, it's a nonsensical operation.
Allin