Dear Statalist,
I am running into some problems trying to run a nonlinear regression. I
continue to get error 480 "starting values invalid or some RHS variables
have missing values." I think I see where my error is but I'm not sure how
STATA deals with a reference, say 'by varname: data[x]' if x is out of the
range of data for that varname. Here is my code: I have written a program
to specify the nonlinear equation, and that is where the error is:
program nlstk2_depreciation
version 8.1
if "`1'" == "?" {
global S_1 "B3 B4 B5 drd2 dmktg2"
global B3=1
global B4=1
global B5=1
global drd2=0.15
global dmktg2=0.15
exit
}
forvalues x=10/53 {
by coname: replace `1'=$B3+$B4*(ireal46[`x'] +
(1-$drd2)*ireal46[`x'-1] + (1-$drd2)^2*ireal46[`x'-2] +
(1-$drd2)^3*ireal46[`x'-3] + (1-$drd2)^4*ireal46[`x'-4] +
(1-$drd2)^5*ireal46[`x'-5] + (1-$drd2)^6*ireal46[`x'-6] +
(1-$drd2)^7*ireal46[`x'-7]+ (1-$drd2)^8*ireal46[`x'-8] +
(1-$drd2)^9*ireal46[`x'-9]/$drd2) + $B5*(imktg[`x'] +
(1-$dmktg2)*imktg[`x'-1] + (1-$dmktg2)^2*imktg[`x'-2] +
(1-$dmktg2)^3*imktg[`x'-3] + (1-$dmktg2)^4*imktg[`x'-4] +
(1-$dmktg2)^5*imktg[`x'-5] + (1-$dmktg2)^6*imktg[`x'-6] +
(1-$dmktg2)^7*imktg[`x'-7] + (1-$dmktg2)^8*imktg[`x'-8] +
(1-$dmktg2)^9*imktg[`x'-9]/$dmktg2) if `x'==year
}
end
I have panel data for companies over a period of years, although each
company has a different amount of years of data (no company has more than 53
years of data). If a company has 10 years of data, I want the regression to
use all 10 years of data. If it has more than 10 years of data, I want it
to use the most recent 10 (say, years 1990-1999), then use the next 10
(years 1989-1998), and so on until it gets to the last set of 10 years for
that company. I think the logic of the equation I have written works out,
so I'm guessing the error is coming from some referencing problem in the
brackets...I don't quite understand how STATA would deal with ireal46[49] if
some company didn't have a 49th ireal46 entry.
Any insights?
Thanks,
Terra
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