.-
help for ^sttody^                                           (STB-40: ssa10)
.-

Converting st data to dy data
-----------------------------

^sttody^ varname varname [^,^ ^fc^odes^(^codes^)^ ^sc^ale^(^#^)^ ^by(^varlist^)^]


Description
-----------

The two varnames are new variables to contain the event
count, d, and the rate denominator, y. If there is no ^by^ 
option, one record is created for each unique value of the id variable 
declared in ^stset^. Thus, when there are multiple records with the 
same id, the size of the dataset is reduced. Any time-varying 
variables will take on their first recorded value in the reduced data set.
The ^by^ option limits this collapsing down of multiple records 
into groups specified by a list of categorical variables. For example,
all records for the same subject and which refer to the same age band 
could be aggregated to form the new record by using a 
^by(^ageband^)^ option.

If no id variable is set, each record is taken as referring to a 
unique subject.


Options
-------

^fcodes( )^ specifies the codes to be treated as failures,
all others to be treated as censoring. 

^scale( )^specifies the units for the analysis time scale - that is, 
units for y, the rate denominator. 

^by( )^ specifies the variables by which the data will be disaggregated
within subject id.


Examples
--------

^sttody d y, fcodes( 1 3 13) scale(365.25) by(ageband)^


Authors
-------

      David Clayton
      MRC Biostatistical Research Unit
      Cambridge
      email: david.clayton@@mrc-bsu.cam.ac.uk

      Michael Hills
      London School of Hygiene and Tropical Medicine (retired)
      email: mhills@@regress.demon.co.uk


Also see
--------

    STB:  STB-40 ssa10
On-line:  help for @stset@, @stlexis@, @dyrate@, @dymh@