Overall design concerns

[rushdi98]

Dear all,

I have written this efficient design script for my choice experiment, but since its my first time doing an experimental design, I would really appreciate it if someone could check it for me before I run it so that I avoid mistakes. I have read alot of posts on this forum which have been realy useful, and I'm really grateful for the help this community gives.


;alts = car, put, cs

;rows = 30
;block = 3

;eff = (mnl,d,mean)

;con

;bdraws = sobol(2000)

;alg = mfedorov

;model:

U(car) =

beta_car_accegr[(n,
-0.012234929064086,
0.0142453314189537)]
* AccEgr_car[10, 15, 20]

+ beta_car_tt[-0.0252509890545476]
* TT_car[45, 55, 65]

+ beta_car_search[(n,
-0.00167278578948678,
0.0170252592952694)]
* Search_car[1, 5]

+ beta_car_tc[(n,
-0.0431167293062408,
0.0580898649146091)]
* TC_car[3, 4, 5]

+ beta_car_pc[-0.0598716980956188]
* PC_car[1, 5, 10]

/

U(put) =

asc_put_d[(n,
0.244648021102231,
0.629330472633128)]

+ beta_put_accegr[-0.0175993317527122]
* AccEgr_put[1, 5, 10]

+ beta_put_tt[-0.0192997948718738]
* TT_put[55, 65, 75]

+ beta_put_tc[-0.0648116534705902]
* TC_put[1, 3.5, 5.5]

/

U(cs) =

asc_cs_d[-1.90766885586331]

+ beta_cs_accegr[-0.0397663282829118]
* AccEgr_cs[1, 5, 10]

+ beta_cs_tt[-0.0210844616143259]
* TT_cs[45, 55, 65]

+ beta_cs_search[(n,
-0.0100297329304847,
0.0394909636434951)]
* Search_cs[1, 5]

+ beta_cs_tc[-0.0205571483243145]
* TC_cs[9.5, 16, 24]

+ beta_cs_avail[(n,
0.00001,
0.00538200778872485)]
* Avail_cs[10, 50, 100]

$


The Bayesian specification is applied to the statistically insignificant parameters which have the correct sign (except for beta_cs_avail which was insignificant and had the wrong theoretical sign, so I am using 0.00001 to indicate the expected direction). the parametes that were significant and had corret signs are specified as fixed point priors.

Is this correct please? especially that the mean of beta_cs_avail is really small (0.00001) in this case which is much smaller than its standard deviation?!

And also the number of sobol draws, is 2000 enough or I should change it? I am planning to let the design run for around 22 hours.

Another thing is that I am expecting to collect only around 50 samples (each respondent getting 10 choice tasks), is the number of rows and blocks sufficient in this case?

Sincerely,
Rushdi