DATA Subcommand (CONJOINT command)

DATA identifies the file containing the subjects’ preference scores or rankings.

  • DATA is followed by a quoted file specification for an external IBM® SPSS® Statistics data file or a currently open dataset containing the data. An asterisk instead of a file specification indicates the active dataset.
  • If the DATA subcommand is omitted, the active dataset is assumed by default. However, you must specify at least one IBM SPSS Statistics data file on a DATA or PLAN subcommand. The active dataset cannot be specified as both the plan file and data file.
  • One variable in the data file can be a subject identification variable. All other variables are the subject responses and are equal in number to the number of experimental and holdout profiles in the plan file.
  • The subject responses can be in the form of ranks assigned to an ordered sequence of profiles, scores assigned to an ordered sequence of profiles, or profile numbers in preference order from most liked to least liked.
  • Tied ranks or scores are allowed. If tied ranks are present, CONJOINT issues a warning and then proceeds with the analysis. Data recorded in SEQUENCE format, however, cannot have ties, because each profile number must be unique.

Example

DATA LIST FREE /SUBJ RANK1 TO RANK15.
BEGIN DATA
01  3  7  6  1  2  4  9 12 15 13 14  5  8 10 11
02  7  3  4  9  6 15 10 13  5 11  1  8  4  2 12
03 12 13  5  1 14  8 11  2  7  6  3  4 15  9 10
04  3  6  7  4  2  1  9 12 15 11 14  5  8 10 13
05  9  3  4  7  6 10 15 13  5 12  1  8  4  2 11
50 12 13  8  1 14  5 11  6  7  2  3  4 15 10  9
END DATA.
SAVE OUTFILE='/DATA/RANKINGS.SAV'.
DATA LIST FREE /CARD_ WARRANTY SEATS PRICE SPEED.
BEGIN DATA
 1 1 4 14000 130
 2 1 4 14000 100
 3 3 4 14000 130
 4 3 4 14000 100
 5 5 2 10000 130
 6 1 4 10000 070
 7 3 4 10000 070
 8 5 2 10000 100
 9 1 4 07000 130
10 1 4 07000 100
11 5 2 07000 070
12 5 4 07000 070
13 1 4 07000 070
14 5 2 10000 070
15 5 2 14000 130
END DATA.
CONJOINT PLAN=* /DATA='/DATA/RANKINGS.SAV'
  /FACTORS=PRICE (ANTIIDEAL) SPEED (LINEAR)
   WARRANTY (DISCRETE MORE)
  /SUBJECT=SUBJ /RANK=RANK1 TO RANK15.
  • The first set of DATA LIST and BEGIN–END DATA commands creates a data file containing the rankings. This file is saved in the external file RANKINGS.SAV.
  • The second set of DATA LIST and BEGIN–END DATA commands defines the plan file as the active dataset.
  • The CONJOINT command uses the active dataset as the plan file and uses RANKINGS.SAV as the data file.