Step 3 of 4
Which differences are actually likely to create tension?
The Index scores each remaining gap by how often it comes up and how hard it is to get away from. It reads the trip by its frictions, not its people.
Not all gaps are equal. A 2-point gap on Morning Rhythms will cause more trouble than a 4-point gap on Cultural Curiosity, and here's why:
Friction = gap size × daily exposure × escape difficulty
Gap size
From the Matrix.
Daily exposure
How many times a day does this dimension get decided? Budget, Pace, and Rhythms get decided constantly. Adventure gets decided once, maybe twice, all trip.
Escape difficulty
Can the group split up around it? Nightlife: easy, some people go home at 11. Accommodation: impossible, you're all in the same house.
Sum it across the 12 dimensions and you get the group's Index. But the number matters less than the breakdown. "Your friction is 60% money" is the useful sentence.
The worked example
Budget: gap 3, exposure high, escape hard. The biggest line item by far.
Rhythms: gap 3, exposure high, escape medium — early risers can go get coffee. Second.
Pace and Planning: gap 2, exposure high, escape medium. Real but manageable.
Everything else: near zero.
So the diagnosis isn't "this group is incompatible." It's "this group has one conversation to have, and it's about money."
Coping. The Index predicts where friction comes from, not whether people handle it well. That's what Conflict and Flexibility (dimensions 11 and 12) are for — they don't sit inside the Index, they modify it. A high-friction group that recovers fast beats a low-friction group that sulks.