st: Multiple Imputation on Panel Data: all variables have missing data, and the panels are expanding

[Jennie Day <jennieday@gmail.com>]

Hi out there.  Thanks for having a look at my questions.  I have two:

1)  I am trying to use STATA 12's mi commands to do multiple imputations on a panel dataset where all variables have some missing values (save the unique ID numbers and the time variable).  I am getting confused on whether to register a variable as passive or imputed.  Can anybody tell me what is the standard of care here? 

2) I have a panel dataset where the number of observations has expanded over time.  There are 292 observations in 1993, and 434 observations in 2007.  Is there a way to avoid imputing values for IDs 293-434 in 1993, etc?

Here are some details about my dataset:   

A) I have a panel dataset beginning in 1993 and going to 2007, annually.  

B) I have some variables that have a 1% missing rate and some that have a 10 percent missing rate.  Should I use imputed for the ones with lower non-response rates and passive for the ones with higher non-response rates?

C) All of my variables are continuous.

Thanks in advance,
jennie
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