This is the NYSE Advancers - decliners which the SPX pretty much follows. You can chart it like any index (ADD -NYSE $ADV MINUS $DECL) but I find it more useful in a separate panel with colors for direction.
The level gives an idea of days move (example: plus or minus 500 is not much movement through the session) but I follow the direction as when more stocks...
USAGE
This script guages the probability of an underlying moving a certain amount on expiration day, to aid the popular "0 dte" strategy. The script counts how many next-day moves exceeded a given magnitude in the past, under similar conditions. The inputs are:
mark_mode:
- "open": measures the magnitude as "open to close"--a true 0 dte.
- "previous close": for...
