Thanks Bert.

So far I have not found any way that output a single data set which combines all the imputed data sets (say, 50 imputed data sets). Probably I missed something, but could you share some information about it, maybe a link?

Thank you very much for helping.




ya

From: Bert Gunter
Date: 2012-07-21 16:58
To: xinxi813
CC: r-help
Subject: Re: [R] combined EM dataset for missing data?
Search yourself!

1. Google on "Impute missing data in R"
2. See the ?RSiteSearch  function
3. Go to Rseek.org and enter in keywords.
4. Download and install the sos package and use its search functionality.

R has multiple packages and functions with multiple approaches to
missing data imputation. Choose what you need.

-- Bert

On Sat, Jul 21, 2012 at 4:58 AM, ya <xinxi813@163.com> wrote:
>
> Hi list,
>
> I am wondering if there is a way to use EM algorithm to handle missing data and get a completed data set in R?
>
> I usually do it in SPSS because EM in SPSS kind of "fill in" the estimated value for the missing data, and then the completed dataset can be saved and used for further analysis. But I have not found a way to get the a completed data set like this in R or SAS. With Amelia or MICE, the missing data set were imputed a couple of times, and the new imputed datasets were not combined. I understand that the parameter estimation can still be done in the way of combination of estimates from each imputed data set, but it would be more convenient to have a combined dataset to do some analysis, for example, ANOVA with IVs having more than two categories. In this case, the only way to get the main effect of the whole IV is to estimate parameters in a single data set(as far as I know). If the separated imputed data sets were used, then the main effect showed in the result were for each category of the IV, respectively. I figured sometimes the readers and reviewers would like to see how bi!
>  g the effect for the whole IV instead of the effect of each category of that IV.
>
> This is one of the reasons I can not fully move to R from SPSS. So any suggestions?
>
> Thank you very much.
>
>
>
>
> ya
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>
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-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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Phone: 467-7374
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