SPSS® 12.0 Command Syntax Reference

262 CONJOINT
Options
Data Input. You can analyze data recorded as rankings of an ordered set of profiles, or cards,
as the profile numbers arranged in rank order, or as preference scores of an ordered set of
profiles.
Model Specification. You can specify how each factor is expected to be related to the scores or
ranks.
Display Output. The output can include the analysis of the experimental data, results of simulation
data, or both.
Writing an External File. An SPSS data file containing utility estimates and associated statistics
for each subject can be written for use in further analyses or graphs.
Basic Specification
• The basic specification is CONJOINT, a PLAN or DATA subcommand, and a SEQUENCE,
RANK, or SCORE subcommand to describe the type of data.
• CONJOINT requires two files: a plan file and a data file. If only the PLAN subcommand or
the DATA subcommand, but not both, is specified, CONJOINT will read the file specified
on the PLAN or DATA subcommand and use the working data file as the other file.
• By default, estimates are computed using the DISCRETE model for all variables in the
plan file (except those named STATUS_ and CARD_). Output includes Kendall’s tau and
Pearson’s product-moment correlation coefficients measuring the relationship between
predicted and actual scores. Significance levels for one-tailed tests are displayed.
Subcommand Order
• Subcommands can appear in any order.
Syntax Rules
Operations
• Multiple FACTORS subcommands are all executed. For all other subcommands, only the
last occurrence is executed.
• Both the plan and data files can be external SPSS data files. In this case, CONJOINT can
be used before a working data file is defined.
• The variable STATUS_ in the plan file must equal 0 for experimental profiles, 1 for
holdout profiles, and 2 for simulation profiles. Holdout profiles are judged by the subjects
but are not used when CONJOINT estimates utilities. Instead, they are used as a check on
the validity of the estimated utilities. Simulation profiles are factor-level combinations
that are not rated by the subjects but are estimated by CONJOINT based on the ratings of