/*Written by Janel Hanmer July 2005
Algorithm from Brazier J, Roberts J.  The Estimation of a Preference-Based Measure of Health
from the SF-12.  Medical Care.  2004;42:851-859.
This code uses Model 4 from the paper.
This code was checked against code written by Peter Franks.*/

/*data is presumed to be labeled and coded as follows:
sf2 = moderate activities where 1="limited a lot" to 3="not limited at all"
sf5 = physical limits kind of work where 1="yes" and 2="no"
sf6 = emotional accomplish less where 1="yes" and 2="no"
sf8 = pain interferes with work where 1="not at all" to 5="extremely"
sf10 = lots of energy where 1="all the time" to 6="none of the time"
sf11 = downhearted where 1="all the time" to 6="none of the time"
sf12 = social activities where 1="all the time" to 5="none of the time"
*/

/*Insert path to data file below*/

data SF6D;
	set 'C: . . .';
run;

data SF6D;
	set SF6D;
	sf6d=1;
	if sf2=1 then sf6d=sf6d-.045;
	if sf6=1 or sf5 = 1 then sf6d=sf6d-.063;
	if sf12=4 then sf6d=sf6d-.063;
	if sf12 =3 then sf6d=sf6d-.066;
	if sf12=2 then sf6d=sf6d-.081;
	if sf12=1 then sf6d=sf6d-.093;
	if sf8=3 then sf6d=sf6d-.042;
	if sf8=4 then sf6d=sf6d-.077;
	if sf8=5 then sf6d=sf6d-.137;
	if sf11=5 or sf11=4 then sf6d=sf6d-.059;
	if sf11=3 then sf6d=sf6d-.086;
	if sf11=2 then sf6d=sf6d-.113;
	if sf11=1 then sf6d=sf6d-.134;
	if sf10=2 or sf10=3 or sf10=4 or sf10=5 then sf6d=sf6d-.078;
	if sf10=6 then sf6d=sf6d-.106;
	
	if sf2= 1 or sf6 = 1 or sf12 =1 or sf12=2 or sf8=4 or sf8=5 or sf11=2 or sf11=1 or sf10=6 then sf6d=sf6d-.077;
	
	if sf2= . or sf5=. or sf6=. or sf12=. or sf11=. or sf10=. then sf6d=. ;
run;