Momentum confirmation

Signed momentum over the window: above zero when price is rising, below zero when falling, always a tiny fraction.

It takes the close now and the close window bars ago, works out the fractional change between them (0.001 means a 0.1% move), and divides that by half the window. On the default window of 10 bars that is one fifth of the 10-bar change, so a 0.1% rise over ten minutes reads 0.0002. It has no fixed range and tracks the price change, not the price level: its correlation with close on the sample is about 0.05.

How to read it

The line sits in its own pane below the price, centred on zero, and its values are small fractions.
On defaults, 90% of bars sit between -0.00017 and +0.00018, so the pane looks flat until you zoom in.
Above zero means the close is higher than window bars ago; below zero means lower.
The line stays empty until window + 1 closes have built up.

What it outputs

Signed momentum: The fractional change in close over the window, divided by half the window. Positive when rising, negative when falling, and tiny on SPY one-minute bars.

Settings

window: Bars back the price change is measured, and the warm-up length. Shorter reacts within minutes and flips on small wiggles. Longer smooths the reading and delays the first value. Choppy price shrinks it as the window grows; a steady trend keeps its size.

Pitfalls

The name says confirmation, but the code only measures a scaled price change. Nothing checks it against another signal, so it does not confirm a move.
The code comment says rate of change per period, but dividing by half the window makes the value twice the average per-bar change. Compare readings only at the same window.
On defaults the median bar reads exactly 0, so zero is the common value, not a rare one, and a flat stretch is normal here.