Efficient Designs

[AnnaChi]

Hello,Professor, I'm new here and I'd like to ask a question about D-efficient design:
I currently have five attributes, including three policy attributes(every attribute have two levels:improve and status quo) ,one policy effect(which have two levels:minor improvement and major improvement) and one payment attribute(50,100,200yuan). The specific code is as follows.

Code: Select all

design
;alts = alt1*, alt2*
;rows=12
;block=2
;eff=(mnl,d)
;con
;model:
U(alt1)=b2.dummy[0.0001]*A[1,0]?0=status quo(base),1=improment
+b3.dummy[0.0001]*B[1,0]?0=status quo(base),1=improment
+b4.dummy[0.0001]*C[1,0]?0=status quo(base),1=improment
+b5.dummy[0.0001]*D[1,0]?0=minor improment(base),1=major improment
+b6.dummy[-0.0001|-0.0001]*E[1,2,0]?/
U(alt2)=b2.dummy*A+b3.dummy*B+b4.dummy*C+b5.dummy*D+b6.dummy*E
$

I decided to generate 12 scenarios and then divide them into two parts, but one of the choice set is inconsistent which have no policy(three policy attributes are status quo) while pilicy effect is major improvement. How should I modify this situation?
Anna

[Michiel Bliemer]

I am not exactly sure what you mean with "inconsistent", but perhaps you mean to impose constraints?
Something like:

;cond:
if(alt1.A=0, alt1.D=1)

Otherwise, please reformulate your question as I do not quite understand what you are asking.

Michiel

[AnnaChi]

Dear professor
I am sorry for my unclear expression. My problem is that after I ran the choice set with the above code, I realized that one of the choice sets doesn't match reality. That is, the levels of policy attributes are all status quo, but the level of policy effect is major improvement , which defies normal logic. I would like to ask you how to add constraints to avoid this situation.
Anna

[Michiel Bliemer]

Ok, then my answer was correct. You need to impose constraints to create realistic .

With the default swapping algorithm, you can use if-then constraints in the ;cond property.
With the modified Federov algorithm, you can use reject constraints in the ;reject property.

I refer to the manual for examples of such constraints. Let me know if you need further help in formulating your constraints.

Michiel