/*
file: makezmat.sas
date: June 4, 2004
name: Brad Hammill
modified by: John Preisser
what: creates Z matrix for a 4 parameter association model like expression (6)
of Preisser, Arcury and Quandt, AJE 2003;158:495-501.
*/

options nocenter ls=80;

* camp is the cluster;
data a;
	input camp worker day;
	y = _n_;
	datalines;
1 1 1 
1 1 2 
1 1 3 
1 1 4 
1 1 8 
1 2 6 
1 2 9 
1 2 13 
1 2 14 
2 1 5 
2 1 6 
2 2 12 
2 2 22 
;
run;


proc print data=a;
run;

proc sql;
	create table b as
	select
		a1.y as y1,
		a2.y as y2,
		(a1.camp = a2.camp) as z1,
		(a1.camp = a2.camp and a1.worker = a2.worker) as z2,
		(abs(a1.day - a2.day) < 7) as z3,
		calculated z2 * calculated z3 as z4
	from 
		a as a1,
		a as a2
	where 
		a1.y < a2.y and
                a1.camp eq a2.camp;
quit;


proc print data=b;
run;