Applying a linear constraint on intercepts in SPSS AMOS can be challenging due to its syntax limitations for certain custom constraints. However, it is possible to impose constraints using the Constraints feature available in AMOS. Here's how you can address this:Steps to Apply a Linear Constraint on Intercepts in AMOS Define a New Parameter for the Constraint:Instead of directly placing constraints on the intercepts, define a new parameter that represents the relationship between the two intercepts. For example, if the intercepts are β1\beta_1β1​ and β2\beta_2β2​, and you want to impose a constraint β1=β2\beta_1 = \beta_2β1​=β2​, you can define a new parameter and set it equal for both intercepts. Modify the Path Diagram:Open your AMOS model in the graphical interface. Right-click on the intercept of the first variable, and assign it a parameter name (e.g., Intercept1). Do the same for the second intercept (e.g., Intercept2). Add the Constraint:Click on Plugins in the AMOS toolbar and select Constraint Editor. In the Constraint Editor, you can write an equality constraint (e.g., Intercept1 = Intercept2) or a more complex linear constraint, such as β2=k⋅β1\beta_2 = k \cdot \beta_1β2​=k⋅β1​, where kkk is a constant. Save and apply the constraint. Run the Model:Execute the analysis after setting the constraint. AMOS will use this additional constraint during parameter estimation. Tips for Syntax-Based Constraints Although AMOS syntax is limited, you can specify equality constraints directly using parameter names:For example, if you assign Intercept1 and Intercept2 as parameter names, adding Intercept1 = Intercept2 in the syntax window should work. Alternative Approach: Using R (lavaan) for Greater Flexibility If AMOS proves too rigid, consider switching to R with the lavaan package for structural equation modeling. In lavaan, you can easily specify such constraints in the model syntax: R

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Thanks! This is not nearly as straightforward as it should be... but it is appreciated. It looks like I need to learn R a little more!