Warning in Ngene and How to choose the design?

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Warning in Ngene and How to choose the design?

Postby sukunta » Fri Feb 14, 2020 4:05 pm

Dear Prof.Michiel Bliemer,
My syntax is
Code: Select all
design
;alts=alt1*,alt2*,alt3
;rows=6
;eff=(mnl,d)
;con
;model:
U(alt1)=b0[0.000001]+b1.dummy[0.000001]*format[1,0]+b2.dummy[0.000001]*con_ser[1,0]+b3[-0.000001]*time[10,20,30]+b4.dummy[0.000001|0.000002]*area[1,2,0]+b5[-.000001]*cost[0,50,100]/
U(alt2)=b1*format+b2*con_ser+b3*time+b4*area+b5*cost
$

and the Ngene proposed

Warning: The value of the prior 'b0' is specified again in the same model, the first specification will be used while the repeated one ignored.
my questions are
1. I don't know this warning that affects the Ngene design.
2.The D-error values between 0.174995-0.161644 from that syntax. The design will be chosen is the minimum D-error, value, but could I choose the design that I want one scenario to test actual choice (external validity testing). This design that I chose has the D-error 0.16301 and B -estimate 100.

Sincerely yours,
Sukunta Muadthong
sukunta
 
Posts: 39
Joined: Tue Jan 12, 2016 1:28 pm

Re: Warning in Ngene and How to choose the design?

Postby Michiel Bliemer » Fri Feb 14, 2020 4:19 pm

1. It is a warning to inform you, it is not an error, so all is fine. In some cases, people provide different priors for the same parameter.
2. You can choose any of the designs, you do not necessarily need to take the one with minimum D-error.

Michiel
Michiel Bliemer
 
Posts: 918
Joined: Tue Mar 31, 2009 4:13 pm

Re: Warning in Ngene and How to choose the design?

Postby sukunta » Fri Feb 14, 2020 4:47 pm

Dear Prof.Michiel Bliemer,
Thank you so much.

Sincerely yours,
Sukunta
sukunta
 
Posts: 39
Joined: Tue Jan 12, 2016 1:28 pm


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