by **JvB** » Thu Jun 23, 2022 12:01 am

So, according to S>K/(J-1) there is a minimum of 4 choice tasks that need to be presented. As derived from the literature to have more variety I would take 3*4=12 and multiply it by 2 because for MMNL I have to estimate the double amount of parameters. Is that a resonable approach? Or can I, if I want to present for example 7 tasks just choose any number of rows that is divisible by 7? I am a bit insecure, as I did not find any clear statement on this, so could also choose 70 rows (7 tasks, 10 blocks) because more rows mean more variety which is always better?!

And how can I test my design (which is optimised for MNL) how it performs with MMNL?

Design

;alts = alt1*, alt2*, SQ*

;rows = 24

;block = 3

;eff = (mnl,d)

;alg = mfederov

;require:

SQ.amount = 3, SQ.period = 3

;reject:

alt1.amount = 3 AND alt1.period = 3,

alt2.amount = 3 AND alt2.period = 3

;model:

U(alt1) = b1[-0.4862] * contrib[1.8,3.3,4.8](7-9,7-9,7-9)

+ b2.dummy[1.4049|1.0240|0.4527] * amount[0,1,2,3] ? 0 = 300, 1 = 600, 2 = 900, 3 = unlimited amount

+ b3.dummy[1.0609|0.5951|0.2733] * period[0,1,2,3] ? 0 = 12, 1 = 42, 2 = 72, 3 = unlimited period

/

U(alt2) = b1 * contrib

+ b2 * amount

+ b3 * period

/

U(SQ) = b0[-0.9618]

+ b1 * contrib_sq[1.6]

+ b2 * amount

+ b3 * period

$

Thank you very much for your support!