There are some situations in which you might want to show respondents their attribute importances and/or part-worth utilities at the completion of an ACA survey. ACA enables this by making the part-worths and attribute importances available as system functions that you can display on the screen.
We suggest the following steps:
1. Generate a Text question after the ACA questions. This question can be in any position following the last ACA Pairs question. This question will be used to display the ACA utilities report.
2. There is a template Text/HTML question at the end of the sample ACA study file (located in the Help menu) you can use as a starting point. Follow the patterns in that Text/HTML question (it is helpful to know something about HTML coding when working with this file.) Copy the coding patterns as many times as needed to match your attribute list. You will note that the Text/HTML question refers to system functions that return part-worth utility and importance values. The attribute importances are returned with the function ACAImportance(Attribute#) (or you may use ACAStrictImportance(Attribute#) which controls for reversals). The level part-worths are returned using the function ACAUtility(Attribute#, Level#). In both cases, you will probably want to round them to the nearest integer for display purposes (using the Round function). You can use these functions at any time during an ACA interview (following the priors questions). If you are using the function within a text field (such as Header1, Header2, etc.) that uses HTML instructions, you should enclose the function within [% ... %].
[% ACAImportance(ExerciseName, 4) %] (Returns the value for the importance of attribute 4)
[% ACAUtility(ExerciseName, 6, 3) %] (Returns the value for the utility of the third level of attribute 6)
[% Round (ACAImportance(ExerciseName, 4)) %] (Returns the value for the importance of attribute 4, rounded)
[% Round (ACAUtility(ExerciseName, 6, 3)) %] (Returns the value for the utility of the third level of attribute 6, rounded)
3. When the survey runs on the Web, values will be inserted in place of the functions, and the bars in the bar chart for importances will extend the appropriate lengths to reflect the relative importance of each attribute.
Notes: Utilities are reported as "zero-centered diffs." Importances are reported as values that sum to 100. The utilities are generated by the efficient updating routine used when the ACA Survey runs on the Web. These utilities are very similar to, but not exactly the same, as the final utilities generated by the ACA OLS Utility Calculator.
For each page that includes a report of ACA utilities or importances, the utilities are re-computed "from scratch". This can be computationally intensive for the server. If you show these values over many pages, the computations must be repeated for each page.
If you change the number of attributes, levels in your study, or the text for attributes/levels, make sure to manually change the HTML report to reflect those changes. There are so many aspects about ACA that are automatic that it is easy to forget to do this.