Please do not interpret this as a usual factor analysis. These plots show contrasts between opposing factors, not loadings on one factor. For more discussion, see dimensionality and contrasts.
The effect on the items of the contrast between the oppositely loading persons (Table 24.1) at the top and bottom of the contrast plot is shown here.
Table 24.0 Variance components scree plot for persons
Table 24.1, 24.11 Principal components plots of person loadings
Table 24.2, 24.12 Person Principal components analysis/contrast of residuals
Table 24.3, 24.13 Person contrast by items
Table 24.4, 24.14 Person contrast loadings sorted by measure
Table 24.5, 24.15 Person contrast loadings sorted by entry number
Table 24.99 Largest residual correlations for persons
Responses by up to 9 persons (or on up to 9 items) to the items (or by the persons) with extreme positive loadings and the items (or persons) with extreme negative loadings are identified. These responses are seen to be higher, as expected, or lower than the model predicts. Counts of these are obtained for each person (or item). The persons (or items) showing the biggest impact of this contrast are listed first. Items and persons showing the most contrast are chosen for this Table based on the "Liking for Science" data.
Table 24.3 showis the impact of the first contrast in the person residuals on items:
PUPIL contrast 1 CONTRASTING RESPONSES BY ACTS
+---------------------------------+
| FAVORS TOP |
| TOP 9 PUPILS | BOTTOM 9 PUPILS|
| HIGH EXP. LOW | HIGH EXP. LOW | Items biased towards top 9 persons
+---------------------------------+
| 9 0 0 | 0 0 9 | 23 WATCH A RAT
| 8 1 0 | 0 1 8 | 5 FIND BOTTLES AND CANS
| 7 2 0 | 1 7 1 | 20 WATCH BUGS
+---------------------------------+
+---------------------------------+
| FAVORS BOTTOM |
| TOP 9 PUPILS | BOTTOM 9 PUPILS|
| HIGH EXP. LOW | HIGH EXP. LOW | Items biased towards bottom 9 persons
+---------------------------------+
| 0 4 5 | 0 9 0 | 13 GROW GARDEN
| 0 5 4 | 0 9 0 | 2 READ BOOKS ON ANIMALS
| 0 5 4 | 0 9 0 | 15 READ ANIMAL STORIES
| 0 5 4 | 0 9 0 | 24 FIND OUT WHAT FLOWERS LIVE ON
+---------------------------------+
FAVORS TOP
|
These items score higher on the persons at the top of the Contrast 1 plot in Table 24.1 than the persons at the bottom of the contrast plot
|
FAVORS BOTTOM
|
These items score higher on the persons at the bottom of the Contrast 1 plot in Table 24.1 than the persons at the top of the contrast plot
|
TOP 7 PUPILS
|
Responses for the top 7 persons (or top half of the persons if less than 7) on the Contrast plot
|
BOTTOM 7 PUPILS
|
Responses for the bottom 7 persons (or top half of the persons if less than 7) on the Contrast plot
|
HIGH
|
item response is higher than expected on this many persons
|
EXP.
|
item response is expected (within 0.5 score points) on this many persons
|
LOW
|
item response is lower than expected on this many persons
|
23 WATCH A RAT
|
item entry number and item label.
items with greatest differential performance between TOP and BOTTOM are shown with strongest difference listed first.
|
23 WATCH A RAT
13 GROW GARDEN
|
The effect of the 1st Contrast is more strongly seen in the performance of these two items. Is there something about them that interacts with the set of persons?
|
