Before everybody rushes off to try and explain Fall Factor see this.
Every time I ask this question, I get somebody rushing to explain what FF is. I understand the concept, but I don't understand why it's relevant. Let me rephrase that... Seems to me, what's most relevant is shock force.
Let me draw out an example. I'm on a short leash, 6". I stretch to place an omni, I slip, I fall 12". Fall factor = 2 in this case. Shock force, modest, maybe 2 Kn. That's enough to rattle me, maybe throw out a bad back or induce a case of whiplash.
Now, a more extreme example, I lead 10' up, slip, and fall 20'. Fall factor = 2. As the Thai say, same, same... but different. This time, the shock force is significantly higher, maybe 9 kN. That's enough force to break gear or possibly hurt myself.
I'm not trying to discount the importance of understanding FF, but it seems to me the thing I should be most concerned about is shock force. That's a tangible number that's gonna tell me if I can really hurt myself. Am I missing something here?