The information added to the Search Tree includes the number of propagation events and the effective global domain reduction at each node:

The statistical information about the Initial Propagation is concentrated in the tree root. All nodes are not equal. You can detect if, in failure nodes (red or pink nodes), the failure is discovered early (small node) or late (large node).

It is important to distinguish between the number of propagation events and the global domain reduction because many propagation events can be triggered with little impact on the domain reduction.