Hi Suveyda,
I've had a similar experience with using TSCS data, it can take a very long time,
depending on the circumstances. Regarding the ridge prior, it's good to start with a
value of 0.5 and then move your way up. For example, the code would read: empri =
.05*nrow(data). When you say 40, do you mean you are using a 0.4 ridge prior? If
you're using 40*nrow(data) in your code this may be a source of error.
The time to complete the imputation varies according to a number of things. The first
being the system you are running on and the number of datasets you are imputing (the m).
Given the degree of missingness, the number of observations and the number of variables
you describe, I'm afraid it will take some time. Generally , TSCS data takes much
longer due to the number of interactions. For example, using a much smaller TSCS dataset
with a 0.5 ridge prior took me approximately 4 hours. Using this as a heuristic, I think
your problem will take much longer. Exactly how much longer, though, also depends on your
code and what you're asking Amelia to do.
Might I first suggest having a look at the Amelia manual (particularly sections 4.5-4.8)
here:
http://r.iq.harvard.edu/docs/amelia/amelia.pdf. I think this will guide you through
most of your queries. Also, if you post your code to the list it would be easier to
respond with a better answer about specific things - the key one being whether or not the
syntax is correct.
Hope this helps.
Cheers,
kyle
From: amelia-bounces(a)lists.gking.harvard.edu
[mailto:amelia-bounces@lists.gking.harvard.edu] On Behalf Of Karakaya, Suveyda
Sent: Monday, 18 June 2012 7:38 AM
To: amelia(a)lists.gking.harvard.edu
Subject: [amelia] Imputation too slow , and numerical options for tscs data?
Dear Prof King,
I am new to Amelia. I try to impute a data set with 8400 obs and 32 vars in total, 14
vars have missing obs, some a lot like around 4 000. Since I have many missing obs, I set
the ridge prior to 40, is that correct? I also chose time spline with k=1 and interaction
with cross section, is that also correct option for a tscs data?
My second question is: how long on average does it take to complete imputation? I am
waiting for 12 hours and do not see any progress at all yet, the computer is running but
there is no imputation yet. Is it because I put ridge option to 40 or because of many
logical bounds and log transformations that I set for my vars? Thank you very much
Suveyda Karakaya
PhD Candidate
The University of Tennessee