I have performed the path analysis using the
sem function in R. The model which I fitted consists of both direct and indirect paths. I have some trouble in interpreting the estimates of the SEM coefficients.
- Does R gives the value of total effect = (direct effect + indirect effect) directly or do I have to multiply the coefficients which are on the indirect path and then add them to the coefficients which is on the direct path? This is the usual way of doing path analysis with the raw/absolute correlation coefficients.
For example consider X (independent variable), Y (dependent variable) and M (Mediating variable).
The raw/absolute correlation/ standardized regression coefficients between them are X and Y -0.06; X and M 0.22 and M and Y 0.28 whereas on the path analysis/sem in R, the above coefficients are X and Y -0.13; X and M 0.22 and M and Y 0.31.
- Thus is the total effect of X and Y equal to -0.13?
- Alternatively how should I interpret this coefficient considering the effect of variable M into the account?