# standard stuff up front
use1 =~ use11 + a*use12 + b*use13
use2 =~ use21 + a*use22 + b*use23
use3 =~ use31 + a*use32 + b*use33
use4 =~ use41 + a*use42 + b*use43
# define intercept and slope as latent variables
# with the use latents as "indicators"
intercept =~ 1*use1 + 1*use2 + 1*use3 + 1*use4
slope =~ 0*use1 + 1*use2 + 2*use3 + 3*use4
# regress on ease and prof
intercept ~ ease + prof
slope ~ ease + prof
# factorial/measurement invariance constraints
use12 ~ c*1
use22 ~ c*1
use32 ~ c*1
use42 ~ c*1
use13 ~ d*1
use23 ~ d*1
use33 ~ d*1
use43 ~ d*1
