[EpiData-list] Visit number

epidata-list at lists.umanitoba.ca epidata-list at lists.umanitoba.ca
Fri Jul 18 07:47:07 CDT 2008

Dear Ziad,

Of course a visit number is interresting... if you want visualize your data
and order it by visit number. Having a visit number at your paper forms is
also interresting for the very same reason.

However, most analysis softwares such as R and Stata do not bother with the
visit number while running survival analysis - which I guess you will do
later. :)  For survival analysis the most important data is the date of the
evaluation, somehting indicatig what happened at the period, and a date
indicating the beggining of the period. Most softwares have available
analysis whith time dpending variables - which has a dataset wiht a
structure containing the same patient at several lines - each line a
different period. Of course to do that, there must a unique idenfier for
each patient which will be repeated all the lines where the same patient

Again, visit number is important but not that importatn. As a previous
answered, if you already started your job and you have a lot of data in your
dataset it will be easier to insert a variable indicating visit number.
Otherwise, you could update you qes file with a nwe variable indicating
visit number.

Best regards,
Pedro Emmanuel

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