Raw vs. ZC Diffs utilities

Hello,

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!
asked Feb 4, 2016

answered Feb 4, 2016 by Gold (39,370 points)