Level Scope › Session and profile
The 80% rule
Open outside yesterday's value area, trade back inside it for two consecutive 30-minute periods, and — the rule says — there is an 80% chance of traversing the area. This fires on the second period and draws the value area as a zone.
What it looks like on a chart
A shaded band between the prior VAH and VAL, from the bar that completed the condition.
| Timeframe | Bars of history it reads | Settings | Events, last 30 days |
|---|---|---|---|
| M15 | 400 | 50 rows, session-low origin, one count per touching bar; 30-minute periods counted from the session open | 122 |
| M30 | 400 | 50 rows, session-low origin, one count per touching bar; 30-minute periods counted from the session open | 111 |
Not on H1, H4, D1. It is defined in thirty-minute periods, so it cannot be expressed above M30.
What we measured
The 80 is folklore. The reference page that teaches the rule reports about 60. And our own work on the value area found its boundaries doing nothing a distance-matched control does not. The event ships carrying both numbers and no forecast of our own.
What it does not claim
The 30-minute periods are counted from the session open, so they are the periods the rule actually means — not whatever happens to align with the clock hour.
Where the definition comes from
the 80% rule, as taught