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 |                           MRG_ DATA ITEM                           |
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 MEANING: Marginal (MRG_) data item
 CONTEXT: $INPUT record and NONMEM data set

 USAGE:
 $INPUT ... MRG_ ...

 DISCUSSION:
 MRG_ labels NONMEM's marginal (MRG) data item.  The marginal data item
 is optional.  With a nonobservation record (i.e. MDV=1 or MDV=101), it
 controls  the definition of the value of the PRED item associated with
 the record.  Basically, 0 means the PRED item is the typical value  of
 F,  and  1 or 2 means it is the expectation of F.  (Note that with NM-
 TRAN, F is defined by Y.)  However, the marginal data item  also  con-
 trols  the  definition of the value of any PRED-defined item D that is
 displayed in a table or scatterplot (except items stored in  the  SAVE
 region) and associated with the record.

 Values are:

 0    The PRED item is the typical value of F and a displayed item D is
      either the typical value of the variable  D  or,  if  conditional
      estimates are requested, the conditional estimate of the variable
      D.

 1 or 2
      The values of the PRED  and  D  items  are  determined  by  other
      things: If the Simulation Step is implemented, and ONLYSIMULATION
      is specified, the PRED item is the simulation expectation  of  F,
      over  the  simulated values of eta for all the individuals in the
      data  set  (including  those  individuals  with  no   observation
      records),  and  the  D  item is the simulation expectation of the
      variable D.  If conditional estimates are obtained  (e.g.,  using
      the  POSTHOC  option), the PRED item is the posterior expectation
      of F, over the conditional estimates of eta for  all  individuals
      in  the  data set (that have some observation records), and the D
      item is the posterior expectation of the variable D.   Otherwise,
      the PRED and D items are as with METHOD=0.

      If the expectation is the posterior expectation:

      If MRG_=1, the deletion adjustment is not used.

      If  MRG_=2,  the  deletion adjustment is used.  With the deletion
      adjustment, the posterior expectation for a given  individual  is
      obtained  by  not including in the computed expectation the value
      of the variable evaluated at the conditional estimate of his eta.

 With MRG_=1 or 2, MDV must also be 1 or 101.  This use of  MDV=1  does |
 not  prevent,  as  would  ordinarily  happen, the DV or RES items from
 being plotted.

 A plot of PRED (and of any PRED-defined item not stored  in  the  SAVE
 region)  will only include points from records with MRG_=1, unless one
 explicitly partitions on MRG_.

 If PREDPP is used and NM-TRAN generates MDV, MDV is set to 1  if  MRG_
 is  1  or  2.  If PREDPP is used, NM-TRAN sets MRG_ to 0 (if it is not
 already 0) when EVID is not equal to 0.  LP                            |

 Warning: If PREDPP is used and NM-TRAN generates EVID, it sets  EVID=2 |
 for records with MDV=1 and no dosing information.  This causes MRG_ to |
 be set to 0.  When MRG_ is used, the data set should include  MDV  and |
 EVID data items.  The values should be MDV=1 and EVID=0 when MRG_>0.

 (See expectation example, expectation block).

 REFERENCES: none.


  
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