
Message/Author 

Yue Yin posted on Tuesday, October 09, 2018  9:40 am



Hi, I generated the dichotomous dataset using the probit in SAS. The formulas are: a=1; b=(2 + (item1)*4/(tot_items1)); prob1=1 / (1 + exp(1*a*(0b))); z1=a*(theta  b); L = z1 ge rand('NORMAL'); /* Probit model */; lambda=.707; c=1/sqrt(1lambda**2); min_prob=.12; tau=(probit(min_prob) + (item1)*probit(min_prob)*2/(tot_items1)); prob2=1probnorm(tau); z2=(tau + lambda*theta)*c; P = z2 ge rand('NORMAL'); a2=lambda*c; b2=tau/lambda; then I use Mplus to check if the result are exact the same by using WLSMV, and MLR PROBIT separately. But a,b,tau,lamda parameters are not exact the same as I set in SAS, they are only partially same. The Mplus code for WLMSV PROBIT is as follows, could you tell me why they are not exact the same? VARIABLE: NAMES are child y1y12 p1p12; USEVARIABLES are p1p12 ; CATEGORICAL = p1p12 ; MISSING are . ; ANALYSIS: TYPE = GENERAL; ESTIMATOR = WLSMV; !LINK = PROBIT; PROCESSORS = 2; COVERAGE = .01; parameterization=delta; MODEL: ! Fix loadings for 1PL; LATENT BY p1*.7 (a); LATENT BY p2p12*.7 (a); LATENT@1; 


I would suggest sending a SASrelated question to SEMNET. 

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