An Analysis diagram is a simplified Activity diagram, which is used to capture high level business processes and early models of system behavior and elements. It is less formal than some other diagrams, but provides a good means of capturing the essential business characteristics and requirements.
Robustness diagrams, used extensively in ICONIX, can be created as Analysis diagrams.
Example Diagram: Example Analysis Diagram
Select Analysis diagram elements and connectors from the Analysis pages of the Toolbox.