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Hello,

I am designing a simple between-subject experiment in which the respondents are split into a treatment/control group. My goal is to test whether the treatment affects the preference for the attributes/levels.

In the past, I tried to use the treatment covariates, but I was not successful ...

Hello Michiel,

thanks for the hints.

perhaps add ;con since the constants in your model seem important

Correct, the constants are the main parameters we need to estimate and also we want to evaluate whether an information treatment would significantly change their value, compared to the control ...

Hello,

we want to make a CE study with two labelled varying options and the reference (status quo) fixed alternative.

We have the results of a pilot survey that allowed us to obtain the priors of the parameters from the MNL model estimation.
The GEO and COL parameters were insignificant in the ...

Thank you, Michel.

We shall use the default algorithm.

Maurizio

Hello Michiel,

yes, reflecting on the design I coded, I think we cannot include the ref alternative with a constrained level that is excluded from the other profiles, there would be a perfect match between the ASC and the ref attribute level.

I think we'll go for the labelled experiment with only ...

Hello Michiel,

thanks a lot, very clear and helpful.

My idea is to use a reference alternative that varies according to the respondent's replies, without any pre-defined value. I am not sure whether, in this case, I should put pre-defined levels in the design. I assume that in your code the 0 ...

Dear Michiel,

let me take advantage of this post to ask you a related question.

We are designing a choice experiment to test the preference for meat deriving from an old breed of pig.
We want to use a reference alternative with fixed charateristics (regular fresh ham from modern pig breed).
The ...

Hi John,
you are totally right, it was silly question.
I can get what I want just setting the constant for the status quo option if it is different from all the other alternatives.

This is the code I wrote, it seems to work pretty well.


?Further attempt after suggestions by John Rose
? Here ...

Hello John,

thanks a lot for your feedback, it was very useful


Firstly, OOD will generally ignore the status quo when calculating the D-error. The mathematics for the algorithm does not allow for status quo or no choice, so in this respect, there is an inconsistency between what you are ...

Hello, we are trying to design a choice experiment that in its simplest form has the following syntax

? Model for a hypothetical choice experiment
? Optimal orthogonal in the difference choice designs
? 9 rows, 3 profiles + no-buy option in each row
? model for utility function based on product ...