Perhaps you can help me. I'm wondering how to interpret this output (pasted below). I am trying to determine if "AVG_PSES" has a mediating effect on the relationship between "grade span" and "TOT_GEN". "Grade span" is a dichotomous variable, where 0=elementary and 1=secondary".

When I compare the betas in the "total effect of x on y" and the "direct effect of x on y", it appears that the beta increases when going from total effect to direct effect, since the sign is negative in "total effect" and positive in "direct effect", indicating that there is NO mediation. But am I supposed to compare the absolute value of the betas instead of the real value? If that's the case, then the beta decreased, and there IS mediation.

Model : 4

Y : TOT_GEN_

X : GRADE_SP

M : AVG_PSES

Sample

Size: 715

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OUTCOME VARIABLE:

AVG_PSES

Model Summary

R R-sq MSE F df1 df2 p

.1451 .0211 .9137 15.3448 1.0000 713.0000 .0001

Model

coeff se t p LLCI ULCI

constant 6.8017 .0413 164.5819 .0000 6.7205 6.8828

GRADE_SP -.3226 .0824 -3.9172 .0001 -.4844 -.1609

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OUTCOME VARIABLE:

TOT_GEN_

Model Summary

R R-sq MSE F df1 df2 p

.6329 .4005 86.1646 237.8299 2.0000 712.0000 .0000

Model

coeff se t p LLCI ULCI

constant 23.8523 2.5059 9.5184 .0000 18.9324 28.7722

GRADE_SP .1998 .8084 .2472 .8048 -1.3873 1.7870

AVG_PSES 7.8601 .3637 21.6132 .0000 7.1461 8.5741

************************** TOTAL EFFECT MODEL ****************************

OUTCOME VARIABLE:

TOT_GEN_

Model Summary

R R-sq MSE F df1 df2 p

.0848 .0072 142.4953 5.1589 1.0000 713.0000 .0234

Model

coeff se t p LLCI ULCI

constant 77.3140 .5161 149.8079 .0000 76.3008 78.3273

GRADE_SP -2.3362 1.0286 -2.2713 .0234 -4.3557 -.3168

************** TOTAL, DIRECT, AND INDIRECT EFFECTS OF X ON Y **************

Total effect of X on Y

Effect se t p LLCI ULCI c_ps

-2.3362 1.0286 -2.2713 .0234 -4.3557 -.3168 -.1951

Direct effect of X on Y

Effect se t p LLCI ULCI c'_ps

.1998 .8084 .2472 .8048 -1.3873 1.7870 .0167

Indirect effect(s) of X on Y:

Effect BootSE BootLLCI BootULCI

AVG_PSES -2.5361 .6561 -3.9469 -1.2737

Partially standardized indirect effect(s) of X on Y:

Effect BootSE BootLLCI BootULCI

AVG_PSES -.2118 .0536 -.3222 -.1093