Modeling and Multivariate Methods - SAS

436 Performing Choice Modeling Chapter 16
Transforming Data
Figure 16.47 Parameter Estimate for Travel Time of Daganzo Data
i
The negative coefficient implies that increased travel time has a negative effect on consumer utility or
satisfaction. The likelihood ratio test result indicates that the Choice model with the effect of Travel Time is
significant.
Transforming Data to One Analysis Table
Rather than creating two or three tables, it can be more practical to transform the data so that only one table
is used. For the one-table format, the subject effect is added as above. A response indicator column is added
instead of using three different columns for the choice sets (Choice1, Choice2, Choice3). The
transformation steps for the one-table scenario include:
• Create or open Stacked Daganzo.jmp from the steps shown in Transforming Data to Two Analysis
Tables.
• Add a new column labeled Response and right-click on the column. Select Formula.
• Select Conditional > If from the formula editor and select the column Choice Mode for the expression.
• Type “=” and select Mode.
• Type 1 for the Then Clause and 0 for the Else Clause. Click OK. The completed formula should look
like Figure 16.48.
Figure 16.48 Formula for Response Indicator for Stacked Daganzo Data
• Subset the data table by selecting Subject, Travel Time, and Response and then select Tables > Subset.
Select Selected Columns and click OK. A partial listing of the new data table is shown in Figure 16.49.