Dear All,
I want to generate an unlabelled DCE design, which will have three alternatives where the last alternative would be a no-choice alternative. There are four attributes such as 3 continuous with 3 levels and one dummy coded with 2 levels. I have already conducted a pilot with 40 respondents for each two conservation agriculture studies. Here is my Ngene syntax for your perusal.
Design
;alts = alt0, alt1, alt2
;block = 4, minsum, total(1 mins)
;rows = 36
;eff=(mnl,d)
;rdraws = halton(250)
;model:
U(alt1) = b2 [(n, -0.022641, 0.0222153)] * L [3,6,9] + b3 [(n, -0.0004528, 0.002698)] * A [25,50,75] + b4.dummy [(n,-0.06963,0.1088352)] * M[0,1] + b5 [(n, 0.01657, 0.0044901)] * C[15,30,45] /
U(alt2) = b2 * L + b3 * A + b4 * M + b5 * C
;alg=swap(stop=total(10 mins))
$
Output
D error 0.001254
S estimate 1012.195146 > 100
Design
;alts = alt0, alt1, alt2
;block = 4, minsum, total(1 mins)
;rows = 36
;eff=(mnl,d)
;rdraws = halton(250)
;model:
U(alt1) = b2 [(n, -0.022798, 0.0224982)] * L [3,6,9] + b3 [(n, -0.003948, 0.0027521)] * A [25,50,75] + b4.dummy [(n,0.2821256,0.1101943)] * M[0,1] + b5 [(n, 0.14207, 0.003422)] * C[30,50,70] /
U(alt2) = b2 * L + b3 * A + b4 * M + b5 * C
;alg=swap(stop=total(10 mins))
$
Output
D error 0.003526
S estimate 38.144589 <100
The only difference you could find the subsidy attribute and their levels in each study, represented by c in both cases.
Specific Questions are related to an efficient design.
1: Are the different syntax correct?
2: What could be the possible reason in the first syntax that I got high S estimates?
Thanks