***********************************************************************
* This is a program that illustrates the use of PROC FREQ and PROC    *
* GLM in SAS for performing trend tests.                              *
***********************************************************************;

proc format;
value groupfmt 0='Placebo' 1='20 mg' 2='60 mg' 3='180 mg';
value reactfmt 0='F' 1='S';
run;

data contin;
input group subject response;
cards;
0 01 27
0 02 28
0 03 27
0 04 31
0 05 34
0 06 32
1 01 31
1 02 35
1 03 34
1 04 32
1 05 31
1 06 33
2 01 32
2 02 33
2 03 30
2 04 34
2 05 37
2 06 36
3 01 40
3 02 39
3 03 41
3 04 38
3 05 42
3 06 43
;
run;

proc glm data=contin;
class group;
model response=group;
contrast 'Trend Test' group -1.5 -0.5 0.5 1.5;
title "Parametric Trend Test for Continuous Data";
run;

proc freq data=contin;
tables group*response/jt;
title "Jonckheere-Terpstra Trend Test for Continuous Data";
run;

data binary;
set contin;
if group=0 then dose=0;
if group=1 then dose=20;
if group=2 then dose=60;
if group=3 then dose=180;
if response<32 then react=0;
if response>=32 then react=1;
format react reactfmt.;
run;

proc freq data=binary;
tables react*group/jt trend;
exact jt trend;
title "Jonckheere-Terpstra and Cochran-Armitage Trend Tests for Binary Data";
title2 "Ordinal Scores";
run;

proc freq data=binary;
tables react*dose/jt trend;
exact jt trend;
title "Jonckheere-Terpstra and Cochran-Armitage Trend Tests for Binary Data";
title2 "Dose Scores";
run;