I have a couple of questions regarding different issues. Appreciate any answer.
We have a design with 8 attributes -> 3^3 and 6^5.
1. Is it possible to create a partial profile design with Ngene? That is, we would like to systematically show only 6 out of 8 attributes in any choice set.
2. How does Ngene handle overlaps?
3. Hope next question is not too weird. Concerning the following code, the design output shows that only 1st and 3rd levels of three-level-attributes are compared and the 2nd level is constantly overlapped. In terms of attributes with six levels, first levels are only compared with latter ones, e.g. 1 with 5, 1 with 4, 0 with 4, 2 with 3. What is the systematic behind this? Does Ngene assume a linearity because we did not specify any priors, not even signs? Especially concerning attributes with 3 levels, Ngene seems to imply there is no reason to estimate middle levels.
- Code: Select all
Design
;alts = alt1, alt2
;rows = 120
;block =10
;eff = (mnl,d)
;model:
U(alt1) = b2 * A[15,20,25]
+ b3 * B[0,1,2]
+ b4 * C[0,1,2]
+ b5 * D[0,1,2,3,4,5]
+ b6 * E[0,1,2,3,4,5]
+ b7 * F[0,1,2,3,4,5]
+ b8 * G[0,1,2,3,4,5] /
U(alt2) = b2 * A
+ b3 * B
+ b4 * C
+ b5 * D
+ b6 * E
+ b7 * F
+ b8 * G$
4. Why do we get different results (efficiency and design output) when using "real" values, e.g. 15, 20, 25 which is percentage in this case, instead of 0,1,2?
Thanks.
Andrew