IBM® SPSS® Amos™ 28

Simple user-defined estimands have the following limitations.

1.Each estimand must be defined by a single expression.

2.In a multiple-group analysis, each group must have the same path diagram.

You can estimate multiple simple user-defined estimands in a single analysis.

Simple user-defined estimands are demonstrated in Examples 38 and 39 of the User's Guide. They are implemented using the CValueSimple class.

You can use any valid Visual Basic expression to specify a simple estimand. You can make use of Microsoft's .NET Framework in defining your estimands. For example, you can use the System.Math class to estimate the square root of a parameter named abc by entering the expression

      xyz = Math.Sqrt(p.abc)

An estimate of xyz together with bootstrap standard errors and confidence intervals will then appear in Amos's output in the same way that built-in estimates do. If your model has no variable named abc, so that abc is unambiguously the name of a parameter, you can omit the "p." and just write

      xyz = Math.Sqrt(abc)

Hint: When you type Math, be sure to use an upper case M. Then, type a period after Math and you will be able to choose Sqrt from a list of available functions.

An alternative method for specifying user-defined estimands is completely general and not subject to the above limitations, but is more difficult to use.