The Test Bench › gate

Does The High-Low Index (highs minus lows) actually work?

DEAD

No edge left once tested on a fair footing.

The claim

The High-Low Index (highs minus lows) times market turns — Classic market-breadth canon

What we did

Tested against Buy & hold SPY, 2012-2026, thresholds swept, null-floor controlled.

The result

Result: 0.01 dSharpe (vs buy-hold), OOS

OOS edge +0.01 vs buy-hold; data-mining noise floor ~+0.40 (below it = noise)

Verdict

The most popular high-low construction. OOS +0.01 -- essentially zero edge. Subtracting the upside extreme from the downside one dilutes the half that actually carries the danger.

What the test did and did not do

Almost nobody publishing a backtest says which of these they did. We list the ones we failed as well as the ones we passed.

Tested 2026-06-23. The same treatment, applied to every other system, is on the test bench.