Conceptual model
A conceptual model is a graphical representation of the aspects of a research and how they are related to each other.
In any research a lot of aspects are described and the interrelations between the aspects are being investigated. Very often this is done in an exploratory or in a descriptive research. These types of research have a design with only one observation moment, but even in a single moment a lot of aspects can be part of the study. To give an overview of all relevant aspects a conceptual model is created. The conceptual model is usually based on a literature study, but it does not have to contain all aspects of a theory. Besides that, even new aspects may be added. Read more about these topics on the pages Theory and Model.
A conceptual model is often tested with regression analysis. Moderation and mediation effects in particular can be tested with special types of regression analyses.
Read more about the longitudinal design in our paper: How to create research designs and conceptual models.