Hi everybody, I have a question about designing a DCE. I have 2 unlabeled alternatives (Alt1 and Alt2) and also a no-choice option. I have 4 attributes (X1, X2, X3, X4) with their levels mentioned below: X1: %5 %10 %15 %20 X2: 0=no 1=yes X3: 0=no 1=yes X4: 30 40 50 60 Based on what I read, I created this orthogonal design. Here is the design; %mktruns(4 2 2 4 4 2 2 4) /* factor level list for all attrs and alts */
%mktex(4 2 2 4 4 2 2 4, /* factor level list for all attrs and alts */
n=64, /* number of choice sets */
seed=17) /* random number seed
%mktblock(data=randomized, /* block randomized design */
nblocks=2, /* create 2 blocks of 32 choice sets */
out=blocked, /* output data set for blocked design */
seed=17) /* random number seed */
data key;
input
Brand $ Knd $ Omg $ Mrk $ Price $; datalines;
Alt1 x1 x2 x3 x4
Alt2 x5 x6 x7 x8
None . . . . .
;
%mktroll(design=blocked, /* make choice design from blocked */
/* linear arrangement from %mktblock */
key=key, /* use rules in KEY data set */
alt=brand, /* alternative name variable is Place */
out=work.food64, /* permanent data set for results */
keep=block) /* keep the blocking variable */
proc format;
value knd 1 = ’%5’ 2 = ’%10’ 3 = ’%15’ 4 = ’%20’ . = ’ ’;
value omg 1 = ’no’ 2 = ’yes’ . = ’ ’;
value mrk 1 = ’no’ 2 = ’yes’ . = ’ ’;
value price 1 = $30 2 = $40 3 = $50 4 = $60 . = ’ ’;
run;
data work.food64;
set work.food64;
format knd knd. omg omg. mrk mrk. price price.;
run;
proc print data=work.food64(obs=192);
by set; id set;
run; When I examined the generated choice sets, I noticed that in some choice sets, every level was the same except for price. For example, the choice set shown below; What can I do to avoid these choice sets? Thank you so much!
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