Random Walk Index: is this move bigger than chance?
How the Random Walk Index compares actual price displacement against what a random walk would produce, and how to use it as a trend filter.
Random Walk Index is free on Basis — the button opens a live crypto chart with it already applied. No account, no trial and no limit on how many indicators you add.
Open the chartWhat it measures
The Random Walk Index asks whether a market has travelled further than a random walk of the same volatility would be expected to. If it has, something other than noise is driving it.
It produces two readings — one for upward displacement, one for downward — and the larger one indicates both the direction and the strength of any genuine trend.
The comparison is the useful part. Most trend measures tell you how far price has moved; this one tells you whether that distance is more than volatility alone would have produced, which is a much harder test to pass and a much more meaningful one to fail.
How it is calculated
These are the steps Basis performs, verified against the published definition.
- 1
For each lookback length up to the period, measure the displacement: the current high minus the low of that many bars ago, for the up reading.
- 2
Divide it by the average true range over that span, scaled by the square root of the number of bars — the distance a random walk would cover.
- 3
Take the largest ratio across all lookback lengths. Repeat symmetrically using lows against past highs for the down reading.
Settings
| Setting | Default | Range |
|---|---|---|
| Length | 14 | 1 – 500 |
The default period sets the longest span considered, and because the indicator takes the maximum ratio across every shorter span as well, raising it can only ever find more trends rather than fewer. That makes it a one-directional dial: longer settings detect slower trends and take correspondingly longer to acknowledge that one has ended, and they never become more selective about faster ones.
How to read it
- A reading above one means displacement exceeded what volatility alone would produce over that span — evidence of a trend rather than a drift.
- Readings comfortably above one on the up side and below one on the down side is the cleanest trend signature the indicator produces.
- Both readings low means the market is doing exactly what noise does, and trend-following tools should be stood down.
- Neither reading is bounded above, so an extreme value is a statement about how unusual the move was rather than about how much further it can go.
Where it misleads
The square-root scaling is what makes the comparison to a random walk valid, and it is the part most often dropped. Without it the indicator simply reports displacement over ATR, which grows with the lookback and tells you nothing about whether the move was unusual. The other trap is reading it as a directional signal — a high up-reading says the up-move was real, not that it will continue.
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Updated 2026-08-22 · Educational reference, not financial advice.