IBM® SPSS® Amos™ 28

Create a new observed variable that has missing values for all cases. An observed variable that is created with the Create button should be represented in a path diagram by a rectangle, just as any observed variable is represented.

Amos can estimate the predictive posterior distribution of a missing value on an observed variable, but cannot do so for the value of a latent variable. This is why you might want to employ an observed variable that has only missing values, rather than a latent variable.