I am still working on my first crowd simulation and I ran into another issue using the system. My agents do not avoid each other. I did not notice this when my agent count was low (7) but when I increased the count (36) I notice that they simply walk right through each other.

The avoidance checkboxes in the Crowd Solver node are enabled. Is there something else I have to turn on to make my agents walk around each other?

I have tried populating the Agent Group with some of the various groups in the provided drop down list but none of them seem to have any effect.

It's particle-based, so perhaps your pscale values are too small?
It may also be that the avoidance force's weight is less than other steer forces in your system, so those forces are taking precedence.

I think I figured it out. It was related to agent scale. My agents are FBX files that were exported from Blender. Blender units seem to be 10x larger than Houdini units.

I went back and re-exported all my FBX files lowering the scale from 1.0 to 0.1 in the Blender exporter and now the agents behave a lot better overall. With this new size, they immediately started avoiding each other and moved at a better pace with the default values from the Crowd Simulate shelf tool.