Method
How busy the overnight session is turns out to say a lot about how big the next US cash session will be. It says nothing about direction.
The activity score runs from 0 to 100. It is the overnight activity ratio scaled so that a normal night is 50 and anything at twice normal or more is 100. It is a description of the market, not advice.
What we measure
Overnight trading activity in US index futures from 15:00 to 05:15 Pacific, compared with the same hours over the previous 20 sessions. The lowest fifth of nights is QUIET, the highest fifth is BUSY, and the rest are NORMAL. The cut-offs come from three years of CME history and are fixed in advance.
What we score
A big-move day is a cash session (06:30 to 13:00 Pacific) whose range is more than 1.5 times the median of the previous 20 sessions. About 18% of days qualify.
What it isn't
It's not a signal to buy or sell, and it doesn't say when the move starts. Think of it as a weather forecast for how much the market will move.