User manual SPSS CONJOINT 8.0

[. . . ] SPSS Conjoint 8. 0 TM For more information about SPSS® software products, please visit our WWW site at http://www. spss. com or contact Marketing Department 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. [. . . ] Files are specified with the PLAN and DATA subcommands. The method of data recording is specified with the SEQUENCE/RANK/SCORE subcommands. The following syntax shows a minimal specification for a conjoint analysis of the carpetcleaner study: CONJOINT PLAN=* /DATA='RUGRANKS. SAV' /SEQUENCE=PREF1 TO PREF 22. Specifying the Files The Conjoint procedure requires two files--a plan file and a data file. The plan file can be created using the Orthoplan procedure, as in the example shown in Figure 4-1, or it can be entered into the Data Editor like any data file. If only a plan file or a data file is specified, the CONJOINT command reads the specified file and uses the working data file as the other. The plan file is specified with the PLAN subcommand, and the data file is specified with the DATA subcommand. For example, the command CONJOINT PLAN='CPLAN. SAV' /DATA='RUGRANKS. SAV' specifies that the plan file to be used in the conjoint analysis is cplan. sav, and the data file to be used in the analysis is rugranks. sav. To specify a plan file and use the current working data file as the data file, specify: CONJOINT PLAN='CPLAN. SAV' /DATA=* The asterisk (*) indicates that the working data file should be used as the data file. You can also eliminate the DATA subcommand altogether, and the working data file will automatically be used as the data file. Similarly, you can specify a data file and use the current working data file as the plan file. For example: CONJOINT PLAN=* /DATA='RUGRANKS. SAV' 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 36 Chapter 4 three methods are indicated by the SEQUENCE, RANK, and SCORE subcommands. You must specify one, and only one, of these subcommands. 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. This is how data are recorded if the subject is asked to order the profiles from the most to the least preferred. The researcher records which profile number was first, which profile number was second, and so on. The data in the carpet-cleaner study were recorded this way, as specified by the following syntax: CONJOINT PLAN='CPLAN. SAV' /DATA=* /SEQUENCE=PREF1 TO PREF22. RANK Subcommand The RANK subcommand indicates that each data point is a ranking, starting with the ranking of profile 1, then the ranking of profile 2, and so on. This is how the data are recorded if the subject is asked to assign a rank to each profile, ranging from 1 to n, where n is the number of profiles. A lower rank implies greater preference. For example, if the carpet-cleaner study had recorded data this way, and the variables in the study were named rank1 to rank22, it would be specified by the following syntax: CONJOINT PLAN='CPLAN. SAV' /DATA=* /RANK=RANK1 TO RANK22. SCORE Subcommand The SCORE subcommand indicates that each data point is a preference score assigned to the profiles, starting with the score of profile 1, then the score of profile 2, and so on. This type of data might be generated, for example, by asking subjects to assign a number from 1 to 100 to show how much they liked the profile. A higher score implies greater preference. [. . . ] · If the special character sequence )CARD is specified anywhere in the footer, PLANCARDS will replace it with the sequential profile number in single-profile-formatted output. Having the profile number automatically printed on the profile will help the experimenter to record the data accurately. This character sequence is not translated in listing-file format. Example PLANCARDS TITLE='Profile # )CARD' ' ' 'Circle the number in the scale at the bottom that' 'indicates how likely you are to purchase this item. ' ' ' /FOOTER= '0 1 2 3 4 5 6 7 8 9 10' 'Not at all May or may Certainly' 'likely to not would' 'purchase purchase purchase' '------------------------------------------' /FORMAT=CARD. The above example would produce the following output for the first profile: PLANCARDS 23 Profile # 1 Circle the number in the scale at the bottom that indicates how likely you are to purchase this item. [. . . ]