User manual SPSS CONJOINT 14.0

[. . . ] SPSS Conjoint 14. 0 TM For more information about SPSS® software products, please visit our Web site at http://www. spss. com or contact SPSS Inc. 233 South Wacker Drive, 11th Floor Chicago, IL 60606-6412 Tel: (312) 651-3000 Fax: (312) 651-3668 SPSS is a registered trademark and the other product names are the trademarks of SPSS Inc. No material describing such software may be produced or distributed without the written permission of the owners of the trademark and license rights in the software and the copyrights in the published materials. The SOFTWARE and documentation are provided with RESTRICTED RIGHTS. [. . . ] Enter a profile footer up to 80 characters long. Footers appear at the bottom of the output if you have selected Listing for experimenter and at the bottom of each profile if you have selected Profiles for subjects in the main dialog box. For Profiles for subjects, if the special character sequence )CARD is specified anywhere in the footer, the procedure will replace it with the sequential profile number. This character sequence is not translated for Listing for experimenter. 13 Displaying a Design PLANCARDS Command Additional Features The SPSS command language also allows you to: Write profiles for subjects to an external file (using the OUTFILE subcommand). See the SPSS Command Syntax Reference for complete syntax information. Chapter Running a Conjoint Analysis 4 In this release of SPSS, a graphical user interface is not yet available for the Conjoint procedure. To obtain a conjoint analysis, you must enter command syntax for a CONJOINT command into a syntax window, and then run it. For an example of command syntax for a CONJOINT command in the context of a complete conjoint analysis--including generating and displaying an orthogonal design--see "Using Conjoint Analysis to Model Carpet-Cleaner Preference". For complete command syntax information about the CONJOINT command, see the SPSS Command Syntax Reference. To Run a Command from a Syntax Window From the menus choose: File New SPSS Syntax. . . This opens an SPSS syntax window. E Enter the command syntax for the CONJOINT command. E Highlight the command in the syntax window, and click the Run button (the right-pointing triangle) on the Syntax Editor toolbar. See the SPSS Base User's Guide for more information about running commands in syntax windows. Requirements The Conjoint procedure requires two files--a data file and a plan file--and the specification of how data were recorded (for example, each data point is a preference score from 1 to 100). The plan file consists of the set of product profiles to be rated 15 16 Chapter 4 by the subjects and should be generated using the Generate Orthogonal Design procedure. The data file contains the preference scores or rankings of those profiles collected from the subjects. The plan and data files are specified with the PLAN and DATA subcommands, respectively. The method of data recording is specified with the SEQUENCE, RANK, or SCORE subcommands. The following command syntax shows a minimal specification: CONJOINT PLAN='CPLAN. SAV' /DATA='RUGRANKS. SAV' /SEQUENCE=PREF1 TO PREF22. Specifying the Plan File and the Data File The CONJOINT command provides a number of options for specifying the plan file and the data file. You can explicitly specify the filenames for the two files. For example: CONJOINT PLAN='CPLAN. SAV' /DATA='RUGRANKS. SAV' If only a plan file or data file is specified, the CONJOINT command reads the specified file and uses the active dataset as the other. For example, if you specify a data file but omit a plan file (you cannot omit both), the active dataset is used as the plan, as shown in the following example: CONJOINT DATA='RUGRANKS. SAV' You can use the asterisk (*) in place of a filename to indicate the active dataset, as shown in the following example: CONJOINT PLAN='CPLAN. SAV' /DATA=* The active dataset is used as the preference data. Note that you cannot use the asterisk (*) for both the plan file and the data file. Specifying How Data Were Recorded You must specify the way in which preference data were recorded. Data can be recorded in one of three ways: sequentially, as rankings, or as preference scores. These three methods are indicated by the SEQUENCE, RANK, and SCORE subcommands. You must specify one, and only one, of these subcommands as part of a CONJOINT command. 17 Running a Conjoint Analysis SEQUENCE Subcommand The SEQUENCE subcommand indicates that data were recorded sequentially so that each data point in the data file is a profile number, starting with the most preferred profile and ending with the least preferred profile. [. . . ] These cases are referred to as reversals. Figure 5-13 Number of reversals by factor and subject This table displays the number of reversals for each factor and for each subject. For example, three subjects showed a reversal for price. That is, they preferred product profiles with higher prices. 36 Chapter 5 Running Simulations The real power of conjoint analysis is the ability to predict preference for product profiles that weren't rated by the subjects. These are referred to as simulation cases. [. . . ]