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Hello,Professor, I'm William and I'd like to ask a question about D-efficient design:
I currently have four attributes, including three regular attributes and one payment attribute, where the payment attribute is (50, 100, 150, 200 yuan). The specific code is as follows.

design
;alts = alt1 ...

1. Yes that would be best practice.

2. Yes you can use this design (which is based on uninformative near-zero priors) also for the main survey, although it will be less efficient than creating a new survey based on informative priors based on the pilot study.

Michiel
Thank you very much for your ...

This is due to an error in your syntax. You are writing:

U(alt1) = + b2.dummy[0.001|0.002] * A[1,2,0] + ...

But there is nothing in front of the "+" and Ngene interprets this as a constant. So you just need to remove the "+" from your utility function like this:

U(alt1) = b2.dummy[0.001|0.002 ...

You can ignore D-optimality as this is only really useful with orthogonal designs and when all parameters are orthogonal polynomial coded. The D-error does not look problematic and is case specific. I do not see any issues there.

I would recommend a few changes in your script.

1. Use dummy coding ...

sorry

design

Hello, founder, I am a newcomer to ngene. I have several questions about Ngene that I would like to ask. I wonder if I can get a response from you:

First of all, let me introduce my attributes. I have 6 attributes, with 2-3 levels for each attribute. Now I only know the positive and negative ...