Message/Author 

Ali H. posted on Wednesday, February 08, 2017  9:01 am



Hello, How would you perform a withinsubject comparison in SEM? Let's say that I want to examine the regression path from IQ to Grades in 3 school subjects (math, English, sports). And let's say that I expect the coefficient to be stronger between IQ and math, and weaker between IQ and sports. How can I test this? I can't use multiplegroup SEM here because I don't have different groups. My data comes from one group only. Is there a special feature in Mplus to compare two coefficients (or a formula that I can use)? Thanks! 


Just label the 2 slopes b1 and b2 in the Model command and then use Model Constraint: New(diff); diff = b1b2; 


Hello, I have a followup question of this. If I have standardized coefficients for the regression path from (0.5)IQ and math, and (0.3)IQ and Sports, can I say there is strong association between IQ and math because 0.5>0.3 and they are all standardized coefficients? Thank you so much 


This general analysis question is suitable for SEMNET. 

Amelia Zhai posted on Wednesday, April 18, 2018  8:33 pm



Hi Muthen I want to compare the coefficient of M1's influence on s1 and s2, with control variables c1(company's type, dummy variable) and c2, but the result shows error, could you tell my what's wrong with my command? INPUT INSTRUCTIONS TITLE:csr regression DATA:FILE IS csr.dat; VARIABLE:NAMES ARE m1m4 s1 e1e3 s2 e4e11 c12; USEVARIABLES ARE m1 s1 s2 c12; MISSING=ALL(9) DEFINE: t1=0; if (c1 EQ 1) then t1=1; t2=0; if (c1 EQ 2) then t2=1; t3=0; if (c1 EQ 3) then t3=1 MODEL: t1 t2 t3 c2; s1 ON m1 t1 t2 t3 c2 (p1) s2 ON m1 t1 t2 t3 c2 (p2) MODEL CONSTRAINT: New(diff); diff=p1p2 OUTPUT:Standardized; *** ERROR Unable to expand: C12 Thanks, Amelia 

Amelia Zhai posted on Thursday, April 19, 2018  1:38 am



Apologize, have noticed the variable problem of c12 

Amelia Zhai posted on Thursday, April 19, 2018  2:13 am



Hi Muthen, I wonder how to compare the coefficient difference between two multiple linear regression? for example here are two equations: y1=b0+b1x1+b2x2+e y2=bo+b3x1+b4x2+e How can I compare the difference of b1b3, and b2b4? I noticed your answer above to label, but now I have more than one independent variables in each regression. I tried to do it but it seems wrong. INPUT INSTRUCTIONS TITLE:csr regression DATA:FILE IS csr.dat; VARIABLE:NAMES ARE m1m4 s1 e1e3 s2 e4e11 c1c2; USEVARIABLES ARE m1m4 s1 s2 c1c2; MISSING=ALL(9); DEFINE: t1=0; if (c1 EQ 1) then t1=1; t2=0; if (c1 EQ 2) then t2=1; t3=0; if (c1 EQ 3) then t3=1; MODEL: c1 c2; s1 ON m1 (p1) m2 (p2) m3 (p3) m4 (p4) c1 c2; s2 ON m1 (p7) m2 (p8) m3 (p9) m4 (p10) c1 c2; MODEL CONSTRAINT: New(diff); diff=p1p7; diff=p2p8; diff=p3p9; diff=p4p10; OUTPUT:Standardized; *** ERROR in MODEL command Unknown variable(s) in an ON statement: (P1) Amelia 


Have just one label per line. 

Amelia Zhai posted on Thursday, April 19, 2018  7:33 pm



Thank you Muthen, then my following question is how could I compare each coefficient in the multiple linear regression, since I can only have one lable per line? And what does the comparsion mean if I compare the two labels between two multiple linear regression? I think it does noe refer to a single coefficient? Amelia 


This doesn't restrict you. Just write for example: s1 ON m1 (p1) m2 (p2) m3 (p3) m4 (p4) c1 c2; and then use the diffs you had in Model Constraint. 

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