# Marketing - MaxDiff - Diagnostic - Trace Plots extension

Creates a diagnostic plot of the trace of the parameter estimates.

Takes a MaxDiff hierarchical Bayes output created from Marketing - MaxDiff - Hierarchical BayesMaxDiff hierarchical Bayes and produces trace plots of the mean and standard deviation parameters for the distribution from which individual coefficients are sampled. For more information on how to interpret this output, see this blog post

## Technical details

Whenever hierarchical Bayes analysis is run with multiple classes, an attempt will be made to match class labels between chains (note that it is often not possible to match class labels). If this succeeds, or if only one chain was specified, one set of mean and standard deviation parameters will be shown for each class. If this attempt is unsuccessful, the trace plots will not be able to be displayed.

## 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 R Output Functions");

const menu_location = "Marketing > MaxDiff > Diagnostic > Trace Plots";
var selected_items = project.report.selectedRaw();
var selected_item = selected_items[0];
var selected_group = selected_item.type == "ReportGroup" ? selected_item : selected_item.group;
var plot = selected_group.appendStandardR("Marketing - MaxDiff - Trace Plots", { "formInput": selected_item.guid});
selected_group.moveAfter(plot, selected_item);
project.report.setSelectedRaw([plot]);


## Acknowledgements

Uses the rstan R package.