I want to predict houldout tasks of my CBC within excel.
Which values do I have to sum up? The individiual utilities (raw) or the individiual utilities (ZC diffs)?
How can I include a linear model (price)? Until now I calculated as the example shows below:
Concept 1: Attr1(level 3 - zc diff utility) + Attr2(level 2 - zc diff utility) + Attr3(price - linear - zc diff utility)
Is this right?
Do I just compare to the None option (utiliy ZC diffs) and pick the maximum?
I tried to calculate the zc diffs by my own and compared them to the ssi web output "hb report". I couldn't get the same values. Is there a difference by using a linear variable?
I took the formula:
"For each respondent...
1. Within each attribute, compute the mean utility. Within each attribute, subtract the mean utility from each utility (this zero-centers the utilities within each attribute...which often doesn't have to be done since they are often already zero-centered in their raw form).
2. Then, for each attribute compute the difference between best and worst utilities. Sum those across attributes.
3. Take 100 x #attributes and divide it by the sum achieved in step 2. This is a single multiplier that you use in step 4.
4. Multiply all utilities from step 1 by the multiplier. Now, the average difference between best and worst utilities per attribute is 100 utility points."
Thanks for your help!