residual correlation
when residual variances contain shared variance
identification
option 2:
> mean of factors = 0
> fix the factor variance to 1 for each factor
global model fit
local model fit
modification indices
> indicate how much the X2 will improve (decrease) if that parameter is freed
when there is a cross loading
add the variable to that factor
when there is residual covariance
add the covariance to the residual covariance matrix
parameters