Erasmo--this problem seems constantly to have a "new" wrinkle. Try this:
clear
input firm year y x
1 1980 20 23
1 1981 22 34
1 1982 20 19
1 1984 22 34
1 1985 20 19
1 1986 28 34
1 1987 30 19
1 2004 33 48
1 2005 30 45
1 2006 35 50
2 1980 15 23
2 1981 55 34
2 1982 29 19
2 1983 15 23
2 1984 55 34
2 1985 29 19
2 1986 28 34
2 1987 30 19
end
su year, meanonly
loc ny=r(max)-r(min)+1
loc fy=r(min)
tempfile allyrs
preserve
drop _all
set obs `ny'
g year=`fy'+_n-1
save `allyrs'
restore
append using `allyrs'
fillin firm year
drop if mi(firm)
tsset firm year
sort firm year
g double d=.
qui forv i=3/`=_N-2' {
loc f=`i'-2
loc l=`i'+2
if firm[`f']==firm[`i'] & firm[`l']==firm[`i'] {
cap reg y year in `f'/`l' if firm==firm[`i']
if _rc==0 {
if e(N)>2 {
predict double ye if e(sample), resid
reg x year in `f'/`l' if firm==firm[`i']
predict double xe if e(sample), resid
reg ye xe
replace d=_b[xe] in `l'
drop ye xe
}
}
}
}
li, noo sepby(firm)
On Fri, May 9, 2008 at 11:58 AM, Nick Cox <[email protected]> wrote:
> The -fillin- does not work as you hoped because _no_ observations exist
> anywhere for years 1988-2003. -fillin- rectangularises, rather than
> "fills in"!
>
> You'd need to fix that by hand by explicitly adding some observations
> with those years but missings otherwise. However, for the example data
> given here, that sounds futile if I understand what is being tried, as
> your gap is too big to be bridged, anyway.
>
> Erasmo Giambona
>
> Sorry Austin. Here are the codes and outputs for my questions 1 and 2.
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