attribute-specific constant (ASC)

[Saraw]

Dear Professor Bliemer,
I have looked at a couple of other posts on this forum about including Asc but am still a little confused.
I have an unlabelled design with 3 alternatives ( including optout).
Since there is no information about priors I assumed all priors to be zero.
My question is ,
is it correct to assume zero for the prior of the attribute-specific constant (ASC) for optout. .--> u(optout)=b6[0].
Best regards,
Sara


design
;alts= alt1*, alt2*, optout
;rows= 12
;eff=(mnl,d)
;model:
u(alt1)=b1.dummy[0|0]*color[0,1,2]
+b2.dummy[0]*newtechnique[0,1]
+b3.dummy[0]*functional[0,1]
+b4.dummy[0|0]*method[0,1,2]
+b5*price[4,7,10]/

u(alt2)=b1*color
+b2*newtechnique
+b3*functional
+b4*method
+b5*price/
u(optout)=b6[0]
$

[Michiel Bliemer]

Yes this is correct. You need to include a constant for the optout, and you can set all priors to zero (including the prior for the constant) if you have no information.

Michiel

[Saraw]

Dear professor Bliemer,
Thank you so much for your time and reply.