Stochastic Momentum Index¶
Indicators · Oscillators
Stochastic Momentum Index (Blau) — double-smoothed distance from range midpoint.
The Stochastic Momentum Index (SMI), also from William Blau, is a refined Stochastic. Where the classic Stochastic measures where the close sits relative to the recent low-to-high range, the SMI measures where the close sits relative to the midpoint of that range — and then double-smooths the result. Centring on the midpoint gives a symmetric −100…+100 oscillator (0 = price at the centre of its range) that's smoother and less prone to false extremes than the raw Stochastic.
How it works¶
Over the %K length (10) the block finds the bar's distance from the midpoint of the high-low range, then double-smooths both that distance and the range itself with EMAs over the Double-EMA smoothing (3), producing the SMI line scaled to roughly ±100. A Signal line (EMA over Signal EMA, 3) gives the crossover, with Overbought (+40) / Oversold (−40) zones and OB/OS signals. Bull ↑ / Bear ↓ fire on the signal cross. It plots in a sub-pane around zero.
When to use it¶
Use the SMI as a cleaner, zero-centred alternative to the Stochastic. Because it's smoothed and centred on the range midpoint, its overbought/oversold reads are more reliable and it whipsaws less — the SMI/Signal cross inside an extreme zone is a higher-quality version of the Stochastic's. It suits mean-reversion in ranges and divergence spotting. As ever, an extreme that stays pinned in a strong trend is continuation; filter the regime before fading.
Example¶
A refined range fade: wire bars into the Stochastic Momentum Index, take the OS zone plus an SMI-crosses-Signal-up event via a Crosses Above into a Buy Signal, gated to a non-trending regime by ADX / DMI. Backtest in the Tester and compare against the plain Stochastic.
Tips & gotchas¶
- Midpoint-based and smoothed — cleaner and less twitchy than the raw Stochastic.
- Zero-centred ±100 — 0 means price at the middle of its range.
- Signal cross in a zone is the trigger; divergence is a strong secondary read.
- Distinct from SMI Ergodic — this is Blau's stochastic-based SMI; Ergodic is his TSI-style one.
Related blocks¶
Inputs¶
| Socket | Type | What to wire in |
|---|---|---|
| Bars | bars |
Price bars |
Outputs¶
| Output | Type | Plots as | Description |
|---|---|---|---|
| SMI | series |
Line · sub-pane | Stochastic Momentum Index (≈ -100..100) |
| Signal | series |
Line · sub-pane | EMA of SMI |
| Bull ↑ | signal |
Signal arrows | SMI crosses above signal |
| Bear ↓ | signal |
Signal arrows | SMI crosses below signal |
| OB | signal |
— | SMI above the overbought threshold |
| OS | signal |
— | SMI below the oversold threshold |
Parameters¶
| Parameter | Type | Default | What it does |
|---|---|---|---|
| %K length | number · 2–200 | 10 |
|
| Double-EMA smoothing | number · 1–100 | 3 |
|
| Signal EMA | number · 1–100 | 3 |
|
| Overbought | number · 0.0–100.0 | 40.0 |
|
| Oversold | number · -100.0–0.0 | -40.0 |
|
| SMI color | colour | #42a5f5 |
|
| Signal color | colour | #ef5350 |
Chart guides
This indicator draws reference level(s): overbought, oversold.
Reference auto-generated from the block catalog · category Indicators.