Aggression should be analyzed separately on the flop, turn, and river because ranges evolve as the hand develops.
On the flop, ranges are generally wider. Players can continuation bet and raise with many draws, backdoor possibilities, pairs, and speculative hands. Therefore, facing aggression on the flop does not necessarily mean you are facing a very strong range.
The turn is different. After one betting round and one additional community card, many weak combinations disappear. A player who continues betting aggressively on the turn usually has a more concentrated range.
The river is even more polarized. A large river bet often represents either a strong value hand or a bluff. This creates situations where bluff-catching becomes strategically important.
For a deeper understanding of river decisions, the course can naturally continue with
River bluffing strategy: fold equity and poker analysis. Studying river bluff frequency, blockers, value-to-bluff ratios, and fold equity gives you a much stronger framework for deciding when an aggressive river bet should be called.