You can use the -boot- option in -ice-. The help file says: " With
the boot option, steps 2-4 are replaced by a bootstrap estimation of
beta_star and sigma_star, obtained by regressing yvar on xvars after
taking a bootstrap sample of the non-missing observations. This has
the advantage of robustness since the distribution of beta is no
longer assumed to be multivariate normal."
Fred
On Fri, Oct 9, 2009 at 9:48 AM, McDonald, Catherine
<[email protected]> wrote:
>
> Hello-
>
> I am working with a small data set with missing values for which I am trying to do multiple imputation with ICE. I have some data that are non-normal. Do I have to do transformations? I have seen a reference to Schafer (Analysis of incomplete Multivariate Data 1997) that says there is evidence that imputation methods can work even when the data are not normal. But I did not know if the ICE command would be one of these methods. Is there a ref that would support leaving non-normal data as is for multiple imputation with ICE? Are there steps that I need to take? What options for transformations would be possible?
>
> Thank you very much-
> Catherine
>
>
>
>
> *
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
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--
Fred Wolfe
National Data Bank for Rheumatic Diseases
Wichita, Kansas
NDB Office +1 316 263 2125 Ext 0
Research Office +1 316 686 9195
[email protected]
*
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* http://www.ats.ucla.edu/stat/stata/
