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Interpolation with part worth utilities in Excel simulator

I have conducted a CBC study and estimated HB part worth utilities with LightHouse Studio. I am now building an Excel simulator and would like the Excel simulator to do linear interpolation between price levels tested in conjoint. For example, in conjoint we tested price levels: $2, $4, $6. In my Excel simulator, I want to be able to evaluate preference share for $4.50 which was not tested in conjoint/does not have a part worth utility from CBC HB.

My Excel simulator creates a design vector for each simulated product with value=1 for attribute levels selected for a product and value=0 for attribute levels not selected for a product. This is then multiplied by the utility vector using the SUMPRODUCT() formula to obtain Total utility for each simulated product. The 1/0 coding works for non-interpolated values BUT how do I code the design vector for interpolated values? For example, is this the correct way to code the design vector for $4.50?

Step 1. Proportion of utility range for $4.50: ($4.50-$4)/($6-$4)=0.25.
Step 2. Price attribute design vector (0, 0.75, 0.25) to be multiplied by utility vector:
$2=0
$4=(1-0.25)=0.75
$6=0.25

Thank you.
asked Aug 5, 2019 by anonymous

1 Answer

0 votes
Excel simulators exported from Lighthouse Studio's Choice Simulator already have the ability to interpolate built into the formulas.
answered Aug 5, 2019 by Walter Williams Gold Sawtooth Software, Inc. (20,130 points)
Thank you for the information. Helpful to know this is available in the exported simulator. If I am not using the exported simulator and building my own Excel simulator - is the design vector coding for interpolation I provided above correct? Thank you.
Yes, that is correct.
Thank you again for the helpful information.
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