/*==========================================================================
SF6D US Programme.
 
*Deriving the SF-6D health state classification from the SF-12*.

*Original Author: John Brazier, modified by Joanne Wu to make it run in SAS
*Date: 24 June 2003

*Taken from Brazier JE, Roberts JR, The estimation of a preference-based 
measure of health from the SF-12. (Available from the authors). 
 

*Please note the following before proceeding with the programme*
*SF-12 items are numbered 1-12.
*Programme uses raw (i.e.uncoded) SF-12 item responses.
*Designed for SF-12 version 1 (Ware JE, Kosinski M, Keller S. SF-12: How to score the SF-12 physical and mental health summary scales. 
*The Health Institute, new England medical Centre, Boston, Massachusetts, March 1995) or 2.  For version 1 you will need to convert the response choice scales 
*of SF10 and SF11onto the version II scale which does not have a 'good bit of the time'.  The syntax
*for doing this is presented below.  
*/

/**Converting SF10 and SF11 to version two.**/


rand=uniform(-1);

SF11r=sf11;
/*If (sf11=2)  then sf11r=2;
If (sf11=3 and rand <0.5)  then sf11r=2;
If (sf11=3 and rand>=0.5)  then sf11r=3;
If (sf11=4)  then sf11r=3;
If (sf11=5)  then sf11r=4;
If (sf11=6)  then sf11r=5;*/

SF10r=sf10;
/*If (sf10=2) then sf10r=2;
If (sf10=3 and rand <0.5) then sf10r=2;
If (sf10=3 and rand>=0.5) then sf10r=3;
If (sf10=4)  then sf10r=3;
If (sf10=5)  then sf10r=4;
If (sf10=6)  then sf10r=5;*/

*SF6D*; 

IF (sf2=3) then SFPhys = 1;
IF (sf2=2) then SFPhys = 2;
IF (sf2=1) then SFPhys=3;

If ((sf5=2) and (sf6=2)) then SFRole = 1;
IF (sf5=1) then SFRole = 2;
IF (sf6=1) then SFRole = 3;
IF (sf5=1 and sf6=1) then SFRole = 4;

IF (sf12=5) then SFSocial = 1;
IF (sf12=4) then SFSocial = 2;
IF (sf12=3) then SFSocial = 3;
IF (sf12=2) then SFSocial = 4;
IF (sf12=1) then SFSocial = 5;

IF (sf8=1) then SFPain = 1;
IF (sf8=2) then SFPain = 2;
IF (sf8=3) then SFPain = 3;
IF (sf8=4) then SFPain = 4;
IF (sf8=5) then SFPain = 5;

IF (sf11r=5) then SFMental = 1;
IF (sf11r=4) then SFMental=2;
IF (sf11r=3) then SFMental=3;
IF (sf11r=2) then SFMental=4;
IF (sf11r=1) then SFMental=5;

IF (sf10r=1) then SFVital = 1;
If (sf10r=2) then SFVital = 2;
If (sf10r=3) then SFVital = 3;
If (sf10r=4) then SFVital = 4;
If (sf10r=5) then SFVital = 5;

Most=0;
If (SFPhys=3) then Most=1;
If (SFRole=3) then Most =1;
If (SFRole=4) then Most=1;
If (SFSocial=4) then Most=1;
If (SFSocial=5) then Most=1;
If (SFPain=4) then Most=1;
If (SFPain=5) then Most=1;
If (SFMental=4) then Most=1;
If (SFMental=5) then Most=1;
If (SFVital=4) then Most=1;
If (SFVital=5) then Most=1;

*scoring using consistent version of model 10 (See manual) - mean model with interaction term*;

If (SFPhys=1) then pf1=0;
IF (SFPhys=2) then pf1 = -.045;
IF (SFPhys=3) then pf1 = -.045;

If (SFRole=1) then rl1=0;
IF (SFRole=2) then rl1 = -.063;
IF (SFRole=3) then rl1 = -.063;
IF (SFRole=4 ) then rl1 = -.063;

IF (SFSocial=1) then sc1=0;
IF (SFSocial=2) then sc1=-.063;
IF (SFSocial=3) then sc1=-.066;
IF (SFSocial=4) then sc1=-.081;
IF (SFsocial=5) then sc1=-.093;

If (SFPain=1) then pn1=0;
IF (SFPain=2) then pn1 = 0;
IF (SFPain=3) then pn1 = -.042 ;
IF (SFPain=4 ) then pn1 = -.077 ;
IF (SFPain=5) then pn1 = -.137 ;

If (SFMental=1) then mh1=0;
IF (SFMental=2) then mh1 = -.059;
IF (SFMental=3) then mh1 = -.059;
IF (SFMental=4 ) then mh1 = -.113;
IF (SFMental=5) then mh1 = -.134;

IF (SFVital=1) then v1 =0;
IF (SFVital=2) then v1 = - 0.078;
IF (SFVital=3) then v1 = -.078;
IF (SFVital=4 ) then v1 = -.078;
IF (SFVital=5) then v1 = -.106;

If (Most=0) then mst1=0;
If (most=1) then mst1=-.077;

SF6D = 1 + pf1+rl1+sc1+pn1+mh1+v1+mst1;

LABEL SF6D='Brazier-SF6D';

DROP RAND SF10R SF11R sf1-sf12
SFPhys SFRole SFsocial SFPain SFMental SFVital
pf1 rl1 sc1 pn1 mh1 v1 mst1 MOST;