# Marketing - MaxDiff - Analyze with Ranking Question (Legacy) - Preference Share Variables from Individual-Level Parameter Means (All Alternatives)

This QScript computes preference shares for the alternatives in a MaxDiff experiment using individual-level parameter means.

## Example

This example uses the data from the MaxDiff Case Study. The table on the left shows a SUMMARY of Individual-Level Parameter Means generated using Q's Segments tool. The table on the right shows a SUMMARY of the preference shares generated by this QScript.

## Technical details

### Input data

This QScript uses data from individual-level parameter means from a MaxDiff experiment. The variables should be combined into a Number - Multi question that has the string Individual-Level Parameter Means in the name. The individual-level parameters question can be generated in Q from a segmentation of a ranking question (by right-clicking a node of the tree and selecting Save Individual-Level Parameter Means and Standard Deviations).

Alternatively, the individual-level parameter means can be computed externally and imported into Q as part of a larger data set. In this case:

### Outputs

A new Number - Multi question is generated in the project, and a table is added to the report to show the average of the computed values.

### Logit transformation

The formula used to obtain the share for alternative ${\displaystyle j}$ of an attribute is:

${\displaystyle S_{j}={\frac {e^{\beta _{j}}}{\sum _{j'}e^{\beta _{j'}}}}}$,

where the sum ranges over all of the alternatives, and ${\displaystyle \beta _{j}}$ is the individual-level parameter mean for alternatives ${\displaystyle j}$.

## How to apply this QScript

• Start typing the name of the QScript into the Search features and data box in the top right of the Q window.
• Click on the QScript when it appears in the QScripts and Rules section of the search results.

OR

• Select Automate > Browse Online Library.
• Select this QScript from the list.

## Customizing the QScript

This QScript is written in JavaScript and can be customized by copying and modifying the JavaScript.

• Start typing the name of the QScript into the Search features and data box in the top right of the Q window.
• Hover your mouse over the QScript when it appears in the QScripts and Rules section of the search results.
• Press Edit a Copy (bottom-left corner of the preview).
• Modify the JavaScript (see QScripts for more detail on this).
• Either:
• Run the QScript, by pressing the blue triangle button.
• Save the QScript and run it at a later time, using Automate > Run QScript (Macro) from File.

### Customizing QScripts in older versions

• Create a new text file, giving it a file extension of .QScript. See here for more information about how to do this.
• Modify the JavaScript (see QScripts for more detail on this).
• Run the file using Automate > Run QScript (Macro) from File.

## JavaScript

includeWeb("QScript Functions for Setting Up Experiments");
var type = "Preference Shares";
if (!maxDiffUtilityCalculation(type))
log("QScript Cancelled");
else
log("QScript Finished");