Guys, I could ask some of you individually but it's always better to talk to
several smart guys at a time.
Some of you know I am working on a project for an ART-Forum which explores
the issue of covariates in CBC/HB estimation: Is estimation with covariates
useful?

I have a question: what do YOU THINK is a "strong" covariate? (and let's
assume we know what the true utilities and their dependence on the covariate
are)
I am looking less for a mathematical answer (although it's OK if it is) and
more for a conceptual answer, maybe even with examples. Like: assume we have
a covariate with only 2 levels (i.e., respondents belong to 2 groups): what
should their preferences be like in order for us to be able to say: group
membership a strong covariate / weak covariate? And if we have 3 groups?
Also, I am looking less for a "correct" answer and more for your opinions.

Looking forward to your replies!

Dimitri Liakhovitski
ninah.com

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