st: AW: sqset options: keeplongest vs. trim from Brzinsky-Fay,Kohler, and Luniak, 2006

["Kaulisch, Marc" <kaulisch@forschungsinfo.de>]

Dear Irune,

In my opinion the help file is quite clear.
help sqset and help sq

Trim erases missing values at the beginning and the end of a sequence - resulting in shorter sequences containing no missings. So the original position of the first observation in a sequence is not maintained.

Keeplongest is different from trim if you have missing values inside a sequence:
"The third choice is to keep only the longest available section of each sequence that is not interrupted by gaps.
    This can be achieved with the option keeplongest of sqset." (help sq)

Marc

-----Ursprüngliche Nachricht-----
Von: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Irune López Pérez
Gesendet: Mittwoch, 3. Februar 2010 17:55
An: statalist@hsphsun2.harvard.edu
Betreff: st: sqset options: keeplongest vs. trim from Brzinsky-Fay,Kohler, and Luniak, 2006


Hello statalist members,



We are working with a longitudinal (panel) dataset with missing values only at the beginning and at the end (not in the middle of the sequence). We want to turn the our data into a sequence data set using the sqset command. We are having problems using keeplongest and trim. We really do not understand the difference between them. What does option "keeplongest" do in comparison to option "trim" when we apply "sqset" to declare the dataset to be sequence data? Does it maintain the position of the first observation in the sequence when this is missing? Would it be possible to see an example how these options are applied and see the results of each of them?



Thank you very much.

Irune

 		 	   		  
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