A buy or sell signal is only as good as the group behind it. A signal on a name whose whole sector is rotating in has the tape at its back; the same signal on a name whose sector is being sold is fighting the tape. The board answers that in one look: where the sector ranks among 30 right now, and how many of its names agree. That is the filter, and it takes ten seconds before you act on a signal.
Find the name's sector on the board and read two numbers. The rank says whether money is moving into that group today. Breadth says whether the group agrees: nine of eleven names green is a sector move, two of eleven is one name carrying the basket. A buy signal inside a sector that ranks in the top third with most names green is a different trade from the same signal inside a sector at the bottom with one name green. Some members will not take the second one at all.
A position is easier to hold when its sector keeps climbing and harder when the sector fades while the name holds up alone. The rank re-computes every few minutes, so a glance at the tile tells you whether the group is still with you. Members get the names driving each basket and an alert when a name accelerates on volume, which is often the moment a signal either confirms or fails.
On a red index day most signal services go quiet, because the market filter is off. The board shows the sectors that are green anyway. When banks, oil or nuclear lead while the index falls, that is rotation, and signals inside the leading groups behave differently from the tape as a whole. One founding API member gates an algo on exactly that: sector green, not index green.
Signal fires, find the sector, read rank and breadth, then decide. Ten seconds, every time.