The problem is to define when a variable might be considered as a latent variable. I am interested in how to describe a latent variable, and what are the properties of latent variables.
My twofold question is:
- When you try to explain what a latent variable is, what do you consider as the main differences between a manifest and a latent variable?
- When does factor analysis or item response modeling seem more appropriate ?
Example. On the one hand, if you want to measure fish weight without any instrument, you can devise items to measure it. In this case, do you rely on a latent variable model? On the other hand, social level is sometimes measured directly through answers to a survey with a linear model (or other models) applied to items such as highest diploma, numbers of books at home, numbers of electronics devices, but not by considering a latent variable. But why can't we use a latent variable model in this case?
Thanks in advance.