Re: st: Multivariate Tobit

["Diana Fletschner" <fletschn@u.washington.edu>]

Thank you, Maarten. This is very useful!
Diana


----- Original Message ----- 
From: "Maarten buis" <maartenbuis@yahoo.co.uk>
To: <statalist@hsphsun2.harvard.edu>
Sent: Friday, June 30, 2006 1:15 PM
Subject: Re: st: Multivariate Tobit



> --- Diana Fletschner <fletschn@u.washington.edu> wrote:
> > I am trying to analyze how spouses who save structure their savings
> > portfolio. That is, what percentage of their savings is in joint
> > accounts, or under his name, or under her name. A basic approach
> would
> > be to use three Tobit models given that the three dependent variables
> > are bounded between 0 and 100. However, I want to estimate them
> > jointly as a Multivariate Tobit given that the errors are likely to
> be
> > correlated due to unobserved household characteristics. And, I would
> > like to impose restrictions on the coefficients taking advantage of
> > the fact that we know the sum of the three  dependent variables has
> to
> > equal 100.
> If I understand you correctly you want to model three dependent
> variables: proportion savings in joint account, in her account, and in
> his account, and these proportions should add up to one. -dirifit- will
> jointly estimate a model with multiple proportions as dependent
> variables which should add up to one. One disadvantage is that the
> proportions must be between zero and one and can not include zero and
> one, so you might need to add and subtract some arbitrary small number
> when couples have no money in one of the categories.
>
> HTH,
> Maarten
>
>
> -----------------------------------------
> Maarten L. Buis
> Department of Social Research Methodology
> Vrije Universiteit Amsterdam
> Boelelaan 1081
> 1081 HV Amsterdam
> The Netherlands
>
> visiting adress:
> Buitenveldertselaan 3 (Metropolitan), room Z214
>
> +31 20 5986715
>
> http://home.fsw.vu.nl/m.buis/
> -----------------------------------------
>
>
>
>
>
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