Dear Sawtooth Software community,
browsing though the forum, I recognized I'm not the first to implement holdout tasks in ACBC investigations.
However, I could not find support regarding how to estimate hit rates (based on these holdout tasks), when using the <b>summed price</b> approach.
In contrast to CBC, where HB estimations will provide path-worth utilities (pwu) for all price levels so I could compared utilities for holdout concepts with actual choices from the holdout task, this is different using summed price.
I've determined a base price of 180$ with 10% variations upwards and downwards. Consequently, I'll receive zero-centered pwu for 162$ and 296$. In the free format holdout tasks, concepts are priced with 208$, 215$ and 238$.
I've tried to compute hit rates by breaking down the interval between the absolute price difference and the related absolute zero-centered pwu difference. As 229,39 marks the center of the intervall (296-162=(134/2+162)), this should be the price for which the zero-centered pwu become 0.
For 208$ (smaller then price interval center, assuming positive puw) I used the rule of three to derive pwu:
In Excel -> =(($AG$1-$AD$1)/AD2)*($AG$1-$AE$1)
I did the same for 215$. For 238$ (higher than interval center), I've modified the last bracket to ((296+229,39)-238)*(-1), resulting "successfully" in negative pwu, but still a less negative amount than the upper benchmark of 296$.
As I have not tried anything like this before, I'm very uncertain whether this approach really works. As mentioned before, I'd assume that some must have had these difficulties before and might come up with a functional solution.
Thanks in advance!