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Re: st: problem with levpet command
From
"Brian P. Poi" <[email protected]>
To
[email protected]
Subject
Re: st: problem with levpet command
Date
Wed, 01 Jun 2011 20:45:02 -0400
On 05/31/2011 07:23 PM, Tuki wrote:
Hi there,
I'm attempting to estimate firm-level productivity using panel data.
To do so, I'm using levpet command by Petrin et al(2004).
After removing all the duplicates and missing values and labelling the data
as panel/time-series using xtset/tsset, I keep on receiving error message
"repeated time values within panel". surprisingly, I have no problem working
with opreg command by Yasar et al (2008). What is the solution?!
Any suggestion is highly appreciable.
The most likely cause of this problem is that your panel identifier
variable takes on values with more than about 7 digits. (Somewhat
embarrassingly) our code generates a temporary panel variable of storage
type float, though float variables can't store numbers with more than
about 7 digits of accuracy.
The solution is simple. Say your current panel variable is called "id".
Then
. egen newid = group(id)
and use -levpet- as though "newid" is your panel identifier variable.
-egen, group- creates a new panel variable that starts at one and
increases sequentially, so you won't have a problem with long panel
variable values.
-- Brian Poi
-- [email protected]
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