Hi Iqbal,

1) Yes, each run of multiple imputation and each dataset within a run will produce different imputations. See this paper for more information about multiple imputation in general: http://gking.harvard.edu/files/gking/files/evil.pdf

2) The "Time-Series Variable" will allow Amelia to impute based on time-series information, if that is a relevant feature of your data. See this paper for a description of this method: http://gking.harvard.edu/files/pr.pdf

3) Increasing the number of imputations won't produce "better" imputations, but it can result in better measures of uncertainty in the analysis model that you run after the imputations. With moderate missing data, the marginal improvement beyond 5-10 imputed datasets is low.

Hope that helps!

Cheers,

Matt

~~~~~~~~~~~

Matthew Blackwell

Assistant Professor of Government

Harvard University

url: http://www.mattblackwell.org

On Thu, Nov 19, 2015 at 1:43 AM, Iqbal Hanif <iqbal.hanif.ipb@gmail.com> wrote:

Thanks Mr. Blackwell. I have some questions (again) about Amelia:

1) I have try Amelia with same data for 3 times and Amelia give 3 different answer, this is the consequence of "Multiple Imputation - Expectation-maximization with bootstrapping" method?
2) What the function of "Set as Time-Series Variable"?
3) In output file options, the default of Number of Imputed Datasets is 5 datasets, so it will be give 5 difference imputed value. If I increase the Number of Imputed Datasets, could it will be give better answer (convergence imputed value)?

I am expecting to receive the answers of my questions from you. Thanks for your attention.

Kind regards,
Iqbal Hanif

On 19 November 2015 at 10:27, Matt Blackwell <mblackwell@gov.harvard.edu> wrote:
Hi Iqbal,

From everything you've described, it sounds like you are using AmeliaView correctly. Hope that helps!

Cheers,
Matt

~~~~~~~~~~~
Matthew Blackwell
Assistant Professor of Government
Harvard University
url: http://www.mattblackwell.org

On Wed, Nov 18, 2015 at 9:34 PM, Iqbal Hanif <iqbal.hanif.ipb@gmail.com> wrote:
Thanks for replying, Sir. For information, I use R version 3.2.2. There are some steps that I'm doing with Amelia II package and AmeliaView:

1) I have a data (.csv format, you can see production_index.csv) that contains 2 variable (Date and Production Index). There are 102 observations that consists of date data from January 2007 to June 2015 and the production index data for each month.
2) I make a simulation. I replace some data randomly with NA, so there are 88 data of production index and 14 NA data of production index (you can see production_index_with_miss.csv)
3) I open the Amelia View and then import production_index_with_miss.csv to the Amelia package. When I click "Impute!", the error log appear, and the message at the error log is "Amelia Error Code: 13 You cannot set all variables (or all but one) as ID variables".
4) So I change the date variable into a number from 1 to 102. I re-import production_index_with_miss.csv to the Amelia package and then click "Impute!". After that, there are 5 .csv data that contains the impute data.

Am I do right? Or there are something wrong with my steps? Thanks for your attention.

Kind regards,
Iqbal Hanif

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