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Re: st: Pesaran CD Test - The panel is highly unbalanced

From   Nick Cox <>
Subject   Re: st: Pesaran CD Test - The panel is highly unbalanced
Date   Mon, 2 Jan 2012 01:37:01 +0000

Your claim of balance is contradicted by your own results which show
varying group sizes and a number of observations much less than your N
multiplied by your T.

You refer to user-written -xtcd- and -xtcsd- without explaining that
they are user-written or where they come from.

The authors of these programs are not necessarily Statalist members,
so if you do not get a more detailed answer, you may need to contact
the authors directly for support.

The last error message indicating that Stata can't find -sqrt()- will
be a side-effect of some other problem. Stata does have a -sqrt()-
function; the problem evidently lies in how it is called within one of
the programs you are using, but I can't say more on how that arises.

Please read the Statalist FAQ for advice on how to post questions.


On Mon, Jan 2, 2012 at 12:12 AM, Lim Boon Leong <> wrote:

> I have a balanced panel data set of N=191 and T=6 but when I performed the
> pesaran CD test by using the following command in Stata12,
> . xtreg lbonus ownexr ownex2r ownex3r ceodual ined remcom1 exblock1 L.lmktbk
> L.roa L.ret L.debt L.ltotasset i.year i.sector2, re
> . xtcd, pesaran abs show
> I got the error message r(2001): The panel is highly unbalance. Not enough
> common observations across panel to perform Pesaran's test.
> I am quite puzzled as in the RE model, the followings are reported:
> Number of obs = 526, number of groups = 121, obs per group: min=1, avg=4.3,
> max=5
> Based on the above, my question is: Are 526 observations still insufficient
> to carry out the Pesaran CD test?  And may I know what ate the minimum
> observations required for Pesaran test?
> For the other balanced panel data set with the same N(191) and T (6), when I
> run the Pesaran Test I obtained the error message as shown below after the
> following command:
> .xtreg lsalary ownexr ownex2r ownex3r L.ldiv ceodual ined remcom1 extblock1
> L.lmktbk L.roa L.ret L.debt L.ltotasset i.year, fe
> .xtcsd, pesaran abs
> unkown function*sqrt () r(133)
> From the error message does it mean that for this data set I have sufficient
> common observations across panel to carry out Pesaran test but because of
> the unknown function *sqrt - Stata could not carry out the test?  May I know
> how to solve this problem?

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