I run the code and it works. Relative D-Efficiency decreased from 79 to 66 and D-error increased from 0.15 to 0.18. However, the choice sets are now more realistic. Thank you very much for your support. I learned a lot about creating a discrete choice experiment. I will consider your suggestions for my studies. Also, your documentations are very helpful. Thank you very much for your help. ... View more

Thank you so much. You are very helpful. I want to ask one more thing. There are also choice sets in the design same as the example below. Good features but lower price or vice versa. Should I also write the restrictions for these choice sets? When I add restrictions the D-efficiency score is getting lower. If I want to add another restriction for the example how can I write restriction macro?   Thank you ... View more

Thank you for the quick answer, I run my code again. I get the same results in both versions (D-eff=79.37 and D-error=0.15). As I understand it, there is no problem in determining n as the exact full factorial (n=32). I edited the final version of the code. %MktRuns(2 2 2 4) %MktEx (2 2 2 4, n=32) /*candidate sets*/ proc print; run; %macro res; do i = 1 to nalts; do k = i + 1 to nalts; if all(x[i,] >= x[k,]) then bad = bad + 1; /* alt i dominates alt k */ if all(x[k,] >= x[i,]) then bad = bad + 1; /* alt k dominates alt i */ end; end; %mend; %choiceff(data=design, /* candidate set of alternatives */ model=class(x1-x4/sta), /* model with stdz orthogonal coding */ nsets=8, /* number of choice sets */ flags=2, /* 2 alternatives, generic candidates */ maxiter=60, /* maximum number of designs to make */ seed=12655, /* random number seed */ options=relative, /* display relative D-efficiency */ beta=zero); /* assumed beta vector, Ho: b=0 */ proc print; var x1-x4; id set; by set; run; proc format; value x1f 1=’no’ 2=’yes’; value x2f 1=’no’ 2=’yes’; value x3f 1=’no’ 2=’yes’; value x4f 1=’10’ 2=’25’ 3=’50’ 4=’75’; run; proc print label; label x1 = ’X1’ x2 = ’X2’ x3 = ’X3’ x4 = ’Price’; format x1 x1f. x2 x2f. x3 x3f. x4 x4f.; by set; id set; var x:; run; proc print data=bestcov label; title ’Variance-Covariance Matrix’; id __label; label __label = ’00’x; var x:; run; title; %mktdups(generic, /* duplicate choice sets or duplicate alternatives within choice sets*/ data=best, factors=x1-x4, nalts=2) But I noticed a problem. When I examine the choice sets that were created, I think that some choice sets are not realistic. For example, the choice set shown below; The first alternative has no good features (no no no) but it has a higher price. The second alternative has all the good features (yes yes yes) but has a low price. What can I do to avoid these choice sets?   Thank you very much again ... View more