Re: st: Binary variable after first-differencing

["Austin Nichols" <austinnichols@gmail.com>]

Amess Kevin --
Do you mean to
bys firm (year): gen difdummy=sum(dummy)
?

On 3/5/07, Amess Kevin <Kevin.Amess@nottingham.ac.uk> wrote:
> I would very much appreciate help on the following problem. My panel
> data contain both continuous and binary variables. I want to estimate a
> model in first differences but would like to incorporate a binary
> variable. So that the binary variable is not first-differenced out of
> the equation I want to create difdummy (see below). Basically, I do not
> know how to create difdummy. Below illustrates my data:
>
> Firm    year    dummy           difdummy
> 1       1993    0               0
> 1       1994    0               0
> 1       1995    1               1
> 1       1996    1               2
> 1       1997    0               2
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