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st: AW: AW: lag and lead average comparison from a specific point in panel data
From
"Martin Weiss" <[email protected]>
To
<[email protected]>
Subject
st: AW: AW: lag and lead average comparison from a specific point in panel data
Date
Thu, 11 Mar 2010 09:57:32 +0100
<>
Here is a better version that takes account of your missings in X2:
*************
clear*
inp int ID Year byte(X1 X2 Z)
111 1990 89 21 0
111 1991 29 . 0
111 1992 87 76 1
111 1993 87 98 0
111 1994 45 88 0
222 1990 98 88 0
222 1991 98 44 0
222 1992 45 71 1
999 1990 76 . 0
999 1991 54 43 0
999 1992 65 32 1
999 1993 65 87 0
999 1994 76 32 0
end
bys ID (Year): gen byte indicator=sum(Z)==0
by ID: egen lagtotal=total(indicator*X2)
by ID: egen lags=total(indicator*!mi(X2))
gen lagmean=(lagtotal/lags)*indicator
drop lagtotal lags
li, noo sepby(ID)
*************
HTH
Martin
-----Ursprüngliche Nachricht-----
Von: [email protected]
[mailto:[email protected]] Im Auftrag von Martin Weiss
Gesendet: Donnerstag, 11. März 2010 09:52
An: [email protected]
Betreff: st: AW: lag and lead average comparison from a specific point in
panel data
<>
Here are the means of the lags:
*************
clear*
inp int ID Year byte(X1 X2 Z)
111 1990 89 21 0
111 1991 29 . 0
111 1992 87 76 1
111 1993 87 98 0
111 1994 45 88 0
222 1990 98 88 0
222 1991 98 44 0
222 1992 45 71 1
999 1990 76 . 0
999 1991 54 43 0
999 1992 65 32 1
999 1993 65 87 0
999 1994 76 32 0
end
bys ID (Year): gen byte indicator=sum(Z)==0
by ID: egen lagtotal=total(indicator*X2)
by ID: egen lags=total(indicator)
gen lagmean=(lagtotal/lags)*indicator
drop lagtotal lags
li, noo sepby(ID)
*************
What would the lead mean look like for ID 222?
HTH
Martin
-----Ursprüngliche Nachricht-----
Von: [email protected]
[mailto:[email protected]] Im Auftrag von MoZo
Gesendet: Donnerstag, 11. März 2010 06:59
An: [email protected]
Betreff: st: lag and lead average comparison from a specific point in panel
data
I have a panel dataset which is set up as follow:
ID Year X1 X2 Z
111 1990 89 21 0
111 1991 29 . 0
111 1992 87 76 1
111 1993 87 98 0
111 1994 45 88 0
222 1990 98 88 0
222 1991 98 44 0
222 1992 45 71 1
.
.
.
.
999 1990 76 . 0
999 1991 54 43 0
999 1992 65 32 1
999 1993 65 87 0
999 1994 76 32 0
I am trying to compare the average of X2 in last 2 years and that in lead 2
years from Z=1. In order to do that I create two new variables: one for the
average of 2 lagged years and another for the average of 2 lead years.
I am calculating an average of X2 in last 2 years (2 years lagged) prior to
an event Z (Z=1) in each panel.
This is what I did.
. sort ID Year
. by ID: egen avgX2lag2yr=mean(l(1/2).X2) if Z==1
But I keep getting error as " unknown function l()"
Obviously l(1/2).X2 was not recognized here.
I tried to as follow as well:
by ccode: egen avgX2lag2yr =(l.X2+l2.X2)/2 if Z==1
But in some cases, X2 are missing. So I can't just put a constant number to
average the sum without risking inaccurate result.
Thank you in advance for help.
Mike
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* http://www.ats.ucla.edu/stat/stata/