Table 2.
Psychometric Analyses
| Dimension- ality Analysisa |
IRT Calibration Analysisb |
IRT Scoringc | ||||||
|---|---|---|---|---|---|---|---|---|
| # items |
EFA (eigen- value for first factor) |
CFA model fit (CFI) |
Range of item thresholds (theta) |
Range of item slopes (theta) |
SEM mean of persons (T- score) |
SEM range of persons (T- score) |
% of persons with SEM ≤ 3.0 (T-score) |
|
| a. English | ||||||||
| Social Function | ||||||||
| Ability | 35 | 26.2 | 0.97 | −2.6 to 1.6 | 1.9 to 4.5 | 1.4 | 0.7 to 6.6 | 92.1% |
| Satisfaction | 44 | 32.5 | 0.96 | −2.4 to 1.4 | 2.1 to 4.7 | 1.6 | 0.7 to 6.6 | 90.2% |
| Social Relationships | ||||||||
| Companionship | 6 | 4.8 | 0.99 | −3.0 to 1.0 | 2.3 to 5.7 | 3.3 | 1.8 to 6.6 | 59.0% |
| Emotional | 16 | 12.2 | 0.99 | −3.0 to 1.0 | 2.0 to 5.7 | 2.7 | 1.1 to 5.8 | 71.5% |
| Informational | 10 | 7.6 | 0.99 | −1.9 to 1.4 | 2.5 to 5.1 | 2.6 | 1.5 to 7.2 | 80.7% |
| Instrumental | 11 | 8.6 | 0.99 | −1.9 to 0.7 | 2.6 to 4.4 | 2.9 | 1.3 to 5.7 | 63.9% |
| Isolation | 14 | 10.2 | 0.99 | −1.0 to 2.6 | 1.8 to 4.2 | 2.1 | 1.4 to 4.9 | 84.3% |
| b. Spanish | ||||||||
| Social Function | ||||||||
| Ability | 35 | --- | 0.97 | −1.9 to 1.1 | 2.4 to 4.9 | 1.2 | 0.7 to 3.8 | 92.5% |
| Satisfaction | 44 | --- | 0.94 | −2.3 to 1.3 | 1.8 to 4.4 | 0.8 | 0.6 to 3.1 | 99.5% |
EFA: Exploratory Factor Analysis
CFA: Confirmatory Factor Analysis
CFI: Comparative-fit index (> 0.95: good model fit; > 0.90: acceptable model fit)
IRT: Item Response Theory (see text)
SEM: Standard error of measurement
a
The English sample was randomly split in half for use in either EFA or CFA; only CFA was performed for Spanish. The English sample size was greater than 1,000 for each EFA or CFA, except for Social Isolation (n=418); Spanish sample size, n=644.
b
IRT calibration of items
c
IRT estimation of SEM for individual persons, based on transformation to T-scores (see text)