performs
a non-metric multidimensional unfolding analysis.
DATA:
Two-way, one-mode
(row-conditional, rectangular)
TRANSFORMATION:
Monotnonic
MODEL:
Euclidean distance
Consider
a set of subjects and a set of stimuli where the subjects indicate their
preferences for the stimuli (the judgements need not be of preference; any
asymmetric relation is acceptable). The aim of the program is to position both
stimuli and subjects as points in a space of minimum dimensionality so that,
for each subject, the rank order of the distances from his or her point of maximum
preference in the space (the "ideal point") to the stimuli matches
the subject's preference ordering as closely as possible.
MINIRSA
expects data in a 'row-conditional' format. The data matrix consists of N rows
each of which reflects a particular subject's order of preference for the
stimuli. There are p columns. The various ways in which these may be presented
are detailed below.
MINIRSA
does not accept paired-comparisons data as such but will take the row sums of
such matrices (see MDPREF).
Data
may be input to MINIRSA as ranks, or as scores, in the order most-preferred to
least-preferred, or the reverse.
MINIRSA
also allows for missing data. The value to be regarded as indicating a missing
value should be specified in the PARAMETERS command with the parameter MISSING
: e.g. if 9 is the code for a missing datum then MISSING(9) is the
appropriate instruction.
INPUT
COMMANDS
Keyword
Function NOTES PARAMETERS MINIMUM
ITERATIONS 6 Sets the minimum number of iterations
to MISSING
DATA 0 sets
the data value which is to be regarded MATFORM
0 (Relevant only when
'READ CONFIG' is used.) PRINT
options
(to main output file) PLOT
options
(to main output file) By
default, a Shepard diagram and the joint space only are plotted. PUNCH
options
(to secondary output file) By
default, no secondary output file is produced. PROGRAM
LIMITS
See also
N OF STIMULI [number]
Number of stimuli in the analysis
N OF SUBJECTS [number]
Number of subjects/cases
DIMENSIONS [number]
Dimensions for analysis
LABELS [followed
by a series
Optionally identify the stimuli
of
labels (<=
65 chars
and subjects. The labels should
each on a separate line] identify
first
the stimuli (columns),
then the subjects (rows), of the data
matrix.
1. N OF SUBJECTS may be replaced by N OF ROWS.
2. N OF STIMULI may be replaced by N OF COLUMNS
Keyword Default Value
Function
DATA TYPE 1
1: Data are ranks (I-scales) of column
indices in decreasing
order of preference
2: As 1 but in increasing order of
preference.
3: Data are scores in order of column
indices -
high score means high preference.
4: As 3 but high scores mean
low
preference.
be performed before the convergence test.
as missing data.
0: The input configuration is entered
subjects
and stimuli (rows).
by
dimensions (columns).
subjects
are entered before
stimuli.
1: The input configuration is entered
subjects
and stimuli (columns)
by
dimensions (rows).
Option
Form
Description
INITIAL N x r
Two matrices are produced: the
p x r
coordinates of the subject points;
the stimulus points in the
required dimensions.
FINAL N
x r Similarly two
solution matrices are printed:
p x r
DISTANCES N x N
Three matrices are printed:
p x p
1. the distances between the subject points;
N x p
2. the distances between the stimulus points; and
3. the distances between the subjects and stimuli.
FITTING N x p The
matrix of disparities (DHATs)
RESIDUALS N x p The
matrix of residuals is printed
HISTORY This
keyword generates an extremely detailed
history
of the iterative process. Users are
warned
that this option generates a
large
amount of output!
By default only the final configuration and the final STRESS values are output.
Option
Description
SUBJECTS A
plot of the subject points only
STIMULI
A plot of the stimulus points only
JOINT
The configuration of subject and stimulus
points is plotted.
SHEPARD The
Shepard diagram is produced.
STRESS A plot of STRESS values by iteration
is produced.
POINT
The contribution of each subject to the
overall STRESS
value is plotted.
RESIDUALS A histogram of
residual values is produced.
Option
Description
SPSS
A file suitable for input to SPSS is produced.
The following
values appear:
I : the
subject index no.
J : the
stimulus index no.
IFR : no. of
repeat orderings
n : the
stimulus index no.
INPUT : the
datum according to I,J
FITTING : the
corresponding DHAT value
DIST : the
solution distance between I & J
RESID : the
corresponding residual value
The format of
the file is (4I4, 3F10.4)
STRESS The
STRESS values at each iteration are
output in a
fixed format.
FINAL
A text file of the final configuration
is produced.
Maximum no. of subjects = 100
Maximum no. of stimuli = 100
Maximum no. of dimensions = 5