choice-metrics.com

I wonder if you could comment on a discussion with a colleague over level balance between attributes in a study we are preparing.

Design =3 attributes (T, H, cost)
Each attribute has 5 levels (zero, plus 4 non-zeros)
Sets = 2 treatment options plus a None option

At present zero values for all 3 ...

I guess it depends on what the opt out is -
ie what are people choosing between and what does the opt out represent?

Is it products and the opt out is a "none of these"?
In that case I would have zeros for attribute levels and ASC dummy coded to 1 for that option.

If its management options or ...

Ah, yes, that would explain it!

I see now that the point about syntax of that form in Continuous Attributes section of the manual is only an aside.
This eliminates my next question about the difference between [1:10:1] and [1,2,3,4,5,6,7,8,9,10], since there is, of course, no difference.

many ...

I am having a first go at generating a design with a continuous attribute (price).
I have a problem - with my attempt always crashing ngene.

I start with an efficient design which seems to work ok.

Design
;alts = alt1, alt2, alt3
;rows = 40
;block=4
;eff=(mnl,d)
;model:
U(alt1) = s[(n,0.4,0.2 ...

Andrew

Can you post your ngene syntax?

One can import any design into Sawtooth SSIWEB - in that sense it's just a survey software well equipped to host choice tasks - it has a design element but you've opted to not to use it.

I think the things to check are:
1-your syntax and the design ...

Thanks Michiel

We'll look at what we can do in Excel for now and see what is possible in the next version of Ngene
(although this request is far less important to me than the wish to have interactions on dummy or effects coded attributes)

best wishes
Dan

This is an odd question.

Is there away to specify a fixed subset of sets within a design, and then use Ngene to find optimal additional sets to add.

For example, assume 8 sets are pre-specified (from an efficient design of 8 sets).
I want an efficient 12 set design, where 8 of the sets must come ...

I would like to re-open this topic (after nearly 2 years!) as I have returned to this type of issue.

To recap on the issue:
I have att1 with 4 levels [A,B,C,D]
& att2 with 3 levels [X,Y,Z]

I want a 2 Alt design that will allow me to estimate the interactions between each level of these 2 ...

I am generating a design for a 3 attribute, 2 alternative, experiment
I have a dummy (att1) with 4 levels [A,B,C,D]
I have a second dummy (att2) with 3 levels [X,Y,Z]

I want a design that will allow me to estimate the interactions between each level of these 2 attributes
A*X, A*Y, A*Z………..D*X, D ...