CFA Flashcards
(12 cards)
b parameter
item attractiveness
communality
proportion af variance explained by the factor/model predicted variance
(factor loading x factor variance)/(factor loading x factor variance+residual variance)
squared factor loading
uniqueness
proportion of variance not explained by the factor
1 - factor loading x factor variance
——————————————–
factor loading x factor
variance+residual variance
1 - squared factor loading
identification
option 1 - in the factor
- mean of factor = 0
- variance of factor = 1
option 2 - in the loading
mean of factor = 0
fix 1 factor loading to 1
standardized factor loadings
correlation between factor and variable
square this to get the explained variance (communality)
standardized residual variances
uniqueness
EFA and CFA differences
EFA
> factor structure is unknown
> number of factors is systematically altered
> all items load on all factors
CFA
> number of factors is known from theory
> loadings are derived from theory/expectations
parameter estimation
- principal factoring
> kaiser, scree, parallel
+ no distributional assumptions
+ no improper solutions
- no explicit falsifiable model - ML
> X^2 goodness of fit, RMSEA
> option to only use covariance matrix
+ explicit model
+ falsifiable
- sometimes improper solutions
- multivariate normal distribution of the data
identification
- scaling the latent variable
- results in m^2 restrictions - statistical identification
> k can’t exceed M
> in EFA this can happen if the number of factors in the model is too large
> df = M - k
rotation
- orthogonal
> factors remain uncorrelated
> varimax - oblique
> facotrs are correlated after rotation
> promax
identifying in the common factor variance vs factor loadings
which parameters are affected and which are not
affected
1. factor variance
2. factor loadings
not affected
1. model predicted covariances
2. model predicted variances
3. residual variances
4. X2 statistic
5. intercepts
falsifiable and unfalsifiable structure
unfalsifiable
1. GLB
2. Cronbach’s alpha
> by only considering these, it is not clear how to interpret the reliability, as the underlying structure of the true (parameter estimates) is unknown
falsifiable
(one-)factor model