Search found 8 matches

by zshroff
Wed Jun 20, 2012 7:45 pm
Forum: Support for Ngene Desktop (v1.x)
Topic: Interaction terms with orthogonality and optimal design
Replies: 12
Views: 49525

Re: Interaction terms with orthogonality and optimal design

Thank you once again for your help in designing this choice experiment. My design examining health worker preferences for jobs in a developing country has six/seven dummy attributes coded as dummy variables [0,1] where 1 is the preferred option and one continuous variable (salary offered) [150, 300 ...
by zshroff
Tue Jun 19, 2012 3:38 pm
Forum: Support for Ngene Desktop (v1.x)
Topic: Interaction terms with orthogonality and optimal design
Replies: 12
Views: 49525

Re: Interaction terms with orthogonality and optimal design

Thanks for your suggestions, I am now looking at using an efficient design as an alternative. For each of my attributes , I do know the expected sign ( ie which level would be preferred by a rational decision maker). If I had to implement it

a) how would the design below fare ( after adding ...
by zshroff
Tue Jun 19, 2012 5:14 am
Forum: Support for Ngene Desktop (v1.x)
Topic: Interaction terms with orthogonality and optimal design
Replies: 12
Views: 49525

Re: Interaction terms with orthogonality and optimal design

Hi,
I recently started working with the non-evaluation version of Ngene and getting output, leading to this round of questions.
This was the design I used
Design
; alts=alt1, alt2
; rows=24
;orth=ood
;model:
U(alt1)= b2*A[0,1] +b3*B[0,1] +b4*C [0,1] + b5*D[ 0,1] + b6*E[0,1,2,3] + b7*F[0,1] /
U(alt2 ...
by zshroff
Fri Jun 15, 2012 11:52 pm
Forum: Support for Ngene Desktop (v1.x)
Topic: Interaction terms with orthogonality and optimal design
Replies: 12
Views: 49525

Re: Interaction terms with orthogonality and optimal design

Thanks for your help with this, will be working on the final design soon with the non-evaluation version
Zubin
by zshroff
Tue Jun 12, 2012 5:38 am
Forum: Support for Ngene Desktop (v1.x)
Topic: Interaction terms with orthogonality and optimal design
Replies: 12
Views: 49525

Questions on OOD and Interpretation of PPM in OOD designs

Thank you for your reply. I had a couple of more questions about using OOD algorithms related to the design I have mentioned in the post above.

1) When running the OOD algorithm, the Pearson Product Moment shows a perfectly negative correlation (-1) for the two alternatives of the same attribute ...
by zshroff
Fri Jun 01, 2012 4:20 am
Forum: Support for Ngene Desktop (v1.x)
Topic: Interaction terms with orthogonality and optimal design
Replies: 12
Views: 49525

Re: Interaction terms with orthogonality and optimal design

Thanks for your help, just to follow up on this. As you mentioned, if I want to get an accurate measure of the D optimality with an OOD design, it would be better to create interaction terms for each of my two way interactions. The following question may sound really silly, but I would like to ...
by zshroff
Fri May 25, 2012 9:35 pm
Forum: Support for Ngene Desktop (v1.x)
Topic: Interaction terms with orthogonality and optimal design
Replies: 12
Views: 49525

Re: Interaction terms with orthogonality and optimal design

Thanks. I don't have any information on my priors to put into the utility function. I am sure that I will have a few more questions to ask as I go ahead with designing my experiment.
Thanks once again for your help,
Zubin
by zshroff
Thu May 24, 2012 7:57 pm
Forum: Support for Ngene Desktop (v1.x)
Topic: Interaction terms with orthogonality and optimal design
Replies: 12
Views: 49525

Interaction terms with orthogonality and optimal design

I am conducting an unlabeled DCE to study issues related to job preferences of workers. I would like my design to have 6-8 attributes with 2-4 levels. Attributes and levels are common across both alternative choice sets to be provided. In addition to orthogonality ( or near orthogonality) and ...